Why build your own website?
The biggest reason? You can make your own content, show it off, and no one else 
can tell you what you can or can't do. Its your website! Its your webserver! 
The power is all in your hands.

Another reason is computer literacy. As technology advances, we've become very 
accostum to the "appification" of websites and haaving everything in an instant, 
and using our phones to navigate the internet. Younger generations are now more 
likely to not know what files and directories on a computer are, or how to 
navigate a filesystem simply because they are used to their phones being so 
userfriendly, they never have to directly interact with these files. 

This makes it seem like only those older or tech savvy with computers can make 
a website, when this is absolutely not the case. I made my very first website 
by myself when I was 8 years old on geocities in 2002! Even if the internet
 was simpler at the time, HTML structure is almost unchanged; theres just 
 more  to learn! 
 
Why is this so important?
There are plenty of people (*cough*compn anies*cough*billio naires*cough*
gover nments*cough*) who live off your attention span being short: If you 
don't know how to use a computer (or don't want to learn) you'll be more 
content with how stuff is moderated, and be more content with having things 
slowly stripped away. If you aren't content, you won't know how to change it, 
and will have to just deal with the moderation put in place.

Not knowing how to use a computer limits you from not just learning to make a 
website, but how to save and make your own media archive, and only allows 
those who do control whats on the internet and what can be saved, and I think 
we all know what happens when a select few have a monopoly over something... 
(Hint: its a whole young adult  dystopian novel!)

Its also been the way how those with certain points-of-views have made it so 
far these past 10 years: Because they have their own websites. Social Media 
can take anything down in a heartbeat, but a maintained website/server can 
last for years as long as you have electricity and an internet connection, 
and a well maintained website can have a heafty following good or bad.

Making a website/webserver brings the power of the internet back into the 
hands of who started it: the Users.

"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders, give
orders, cooperate, act alone, solve equations, analyse a new problem,
pitch manure, program a computer, cook a tasty meal, fight efficiently,
die gallantly. Specialization is for insects."
    -- Robert Heinlein, Time Enough for Love[1][2]

TL;DR: A (very brief) internet history:
The internet started out as an archive for the US government in the 1990s, and 
went public in 1995. Known as Web 1.0, this came with static pages on the internet, 
mostly used by colleges, but by the early 2000s anyone could make a website! Social 
places such as a BBS(Bullitein Board System) and Forums began here, and were the 
begginnings of Social Media.

By the mid-late 2000s, as hardware updates made intgernet much much faster and more 
availible to everyone, Social Media began to make the internet more "live", since you 
could interact with things more on Twitter or Myspace than you could a forum. 

As the internet advanced, most forums and static sites have migrated and made way 
for the "Web 2.0". Fan pages have become Wikis and dedicated Tumblrs/Twitter accounts,  
and Discord can be hailed as a very modern and instant take of a forum, having multiple 
categories of  channels in a big server. This has centralized the internet into maintained
"Social Media" sites, owned by growing corperations.

We're very, very lucky that the biggest social media giants have yet to go offline, 
but with sites like Vine's Archive slowly growing more outdated and flash disappearing, 
any social media could soon blip out of existence. Having your own things backed up to 
your own server and displayed on your site can prevent anything you have uploaded already lost.

So what does the next 10 years of internet have in store?
The next 10 years of internet ("Web 3.0") is meant to be de-centralized - NOT controlled 
by big social media sites, but by the users itself like the old web 1.0.

However, many, many people have suggested that web 3.0 will be spearheaded by blockchains and
NFTs, a media so harmful to the envorment that crypto farms alone reversed 5 
years of ozone conservation in 2021. (Please care about the enviroment, were living flesh 
beings on this earth who are susutained by this floating rock being in a "life zone" and 
wihtoput that or an OZone we would be cooked dead otherwise.)

NFTs claim to be single-use tokens on a blockchain, but As many artists know, you cannot 
have just one image of artwork on the internet. Anyone can save this image to their 
computer via right-clicking, screenshots, even taking a picture with your phone can perserve 
and copy the image! Having your own webserver is like an NFT, but its much more physical, 
reliable, and does not destroy the freaking planet. Plus: The whole internet is just a 
bunch of servers, running constantly. Anything can be taken down at any given point.

So, wait, wouldn't running your own webserver contribute to this? No, actually,
since a regular, small webserver is only using ONE CPU, ONE computer, a few harddrives, 
and doesnt need a graphics card to run it, its using much less power than say, a mining 
chain of 50 DIFFERENT MINI COMPUTERS, each with a Graphicas card, running all at ONCE.

Plus, when you download and save media to an external hard drive, you eventually unplug
that extra drive and let it sit "cold" - you only need to run it when you want to browse it.
Otherwise its never using power like a mining farm.