>>323250084
(I haven't watched the original video because it's too long and I already have an opinion on the subject)
It's true that it doesn't change your real life, but it can be a safe haven or a nice reprive where you can feel more at home in a different body.
I like the example of the streamer ironmouse. She's sick and bedridden, and felt like a loner because of this, but being online and using an avatar made her appear just like everyone else (while she's online). Of course it doesn't help with her sickness, but it means a lot to have social interaction on your own terms. 
You can be seen as just what you want to present, how you want to show yourself, instead of what you immediately come across as in real life. And for people who, for one reason or another (gender dysphoria, skin color, handicap) are not comfortable with their "real" body, it makes things a lot easier.