I had a hard time trying to understand what my kid is doing there. The “games” were weird. I have an impression that it was very highly addictive. So it’s gone from my home.
The other thing that concerned me was the amount of adults there just to 'play' i joined a shooting 'game' (just a bunch of stuff to shoot and guns laying around) and there was voice chat included and some guy with an eastern european accent making homophobic jokes and talking about how someone should add lazy mexicans as targets. Not uncommon online, but roblox I had at one time thought was trying to be a childrens platform, boy was I wrong.
I let my SIL know she might want to keep them off that or be present whenever they play. She did not listen until one of my nephews stole her credit card and used it to buy a bunch of crap online.