The translation feature was always there, they just made it so you don't have to press a button to translate a post. Which I guess is nice, but it's like a minor client-side setting. On the other hand, they switched from Google Translate to Grok, which means that now you can't even really trust the translation because, even ignoring the inherent imprecision of an automatic translation tool, Grok is subject to hallucinations has been caught making up posts wholesale.
I find that the translations are way better than they used to, because Grok translates slang and insults more truthfully than Google Translate, and those two things are -- for better or worse -- a large part of the conversations on Twitter.