Yeah, I get we see it as crappy but it is essential for them.
I liked more how they did before where you would buy yearly subscription and they would put money to your kid account every week or month. Shame they stopped that.
They still offer monthly subscriptions, 10% more Robux for the same price if you're willing to subscribe. I am glad I didn't, my son still plays a lot, but after a few months of him blowing every dollar he got on Robux, he has stopped bothering. Partly I think he came to the conclusion that games which allowed players to easily buy their way to supremacy were less fun to play (who wants to be cannon fodder?)