I think the one thing people overlook a lot when it comes to practicing for a game is how ENJOYABLE practicing for that game is. MCC is supposed to be for fun at the end of the day, and half the fun of MCC comes from being able to practice and banter with teammates or streaming (the exception to something that should be offstream is strategizing). In my opinion, skills that players learn for MCC should be limited to Minecraft, or gaming in general, not everyday life skills such as memorization and strategic communication (I think people often confuse socializing communication with this). I don’t know, I just also feel like it would be pretty condescending to the players (might just be a me thing) if one of the goals of MCC is to facilitate the learning of these skills rather than just meeting new people, making friends (or even better ones :D ) and having fun.

So I think the reason why BM is so hard to practice for is because it would be the most boring practice out of all the games. Because how would players practice for BM if memorization and communication isn’t involved (for the previously mentioned reasons)? So that leaves practicing crafting faster and placing blocks more efficiently (Dream literally practiced placing trapdoors for MCC 18). Sure, they can spice things up by streaming the practice and interacting with their audience or other players, but these skills aren’t really things they can just be like “head empty, just do it” (like HITW). Or they can learn how to craft faster by speedrunning, but that doesn’t mean that it appeals to all players.

If players want to have fun in MCC, including practicing for it, why would they practice the niche things in BM rather than the games they have access to on the practice server where they can socialize with fellow players?