It's awful to look at.
Everything disappears into a flood of junk.
No tags.
Hard if not impossible to search for art and/or artists.
Following a few hundred accounts, twitter does not allow me to scroll far enough back after sleeping one night.
There is no gallery, if the artist posts memes or such as reply to others, it floods their Media tab.

Are the artists too lazy to upload to a few places and write tags? They just wanna splooge arts into one place and hope for the best? Who REALLY owns the art you upload to twitter?

If YOU my dear artist cant upload to several places. May i introduce you to your lord and saviour postybirb?
https://www.postybirb.com/

I've seen many an artist use it successfully.

So dear artist who uses twitter as main art site. Why?

Here postybirb https://www.postybirb.com/
use that to upload to several sites at once. I dont care if you dont like the site, i wanna see the art and twitter is awful. Instagram is worse, and it's owned by facebook which makes it double the bad.