There's almost zero proper documentation on BCAT stuff but does it still need to be done in 2024 for the latest 2.0.6 update?

From my own testing, a handful of date events seem to be working just fine as long as in game prerequisites are met. There are a LOT of events once tied to BCAT files though, so I can't really check all of em.

One other point to note - in videos of players using legit switches and copies of the game, the version still seems to be 2.0.6 without a letter (and 🏠 for HHA DLC)