Just goes to show how much our online behavior and trends are determined by algorithms. The translate button has been there for years, but I guess some engineer flipped the "show international tweets on the timeline" button last week and this is the result.
Can confirm Japanese X is great, the translate feature in general is a lot of fun and works incredibly well, I didn't realize the tweets were translated for the longest time.
Note that Japanese X lacks a lot of the political insanity of normal X (or even Bluesky). They mostly discuss culture, hobbies, interests, and daily activity, rather than whatever outrageous thing some political lightning rod is doing at that moment.