Yeah, impulse control is not something they have currently, and the constant nagging of "pay to play X!" and whatnot would build so much FOMO that I just don't want to deal with the constant nagging.
So it's a hard no. I do allow it if their friends want to host a game to play together, but apparently there's now a Bedrock -> Java Minecraft bridge, so I'll just set that up going forward and host my own server so they can play together.
For me it's not about the money necessarily, it's about avoiding the "spend money to get dopamine hit" pattern these games are pushing. If a game needs you to constantly be spending money to enjoy it, it's not a fun game, it's a shopping spree.