Oh UMMMM IDK
What is Play (Beta)?

What is Play (Beta)? What is the difference between that and play live chess
It's a feature of the beta.
https://www.chess.com/news/view/a-place-to-play-live-and-daily-play
Did you turn on Beta in your settings by chance?

Sometimes the site rolls out feature to a small subset of the membership at a time to load test features. It's possible they have begun that process to get additional feedback.

premoves were always available. there is a gear next to play live boards where u can enable premoves.
I also received this Beta update without my consent and there is no way to turn it off. It is slowing down my computer drastically, making live play impossible.
I would like to join the Beta version, but I need to get Activity points. How to do it?
You can get activity points by talking in forums. Once you get enough, you can just go to settings and find the beta option at the bottom of the page. This post is not about the Beta testing by the way, I think it's just when the Play page was in Beta, but it's now the main playing page we are using already.
What is Play (Beta)? What is the difference between that and play live chess