Roblox just as the single entry point in stores (for the most part) and doesn't clutter search engines when people are looking for the real games (for the most part) and has a certain friction between verisimilitude and aesthetic. For the most part the Roblox version of a game looks like Roblox, you aren't going to confuse it for "the real thing". Needing to use Roblox bucks instead of USD is going to be a red flag for some that they aren't getting a "professional" experience (and for others means they have an easier time playing it because their parents won't give them prepaid credit cards but will give them Roblox gift cards).

It's not just that the bar to entry is that much lower than Roblox's already low bar, but that the ceiling for (mass) deception is now much higher.