Sadly, if online, most people bypass it. Unless with ID verification,
which pragmatically causes lots of public relations
damage and privacy concerns, as there are cases where
information is leaked by other people.
However, even out of that, having a set age minimum for certain things
arbitrarily might be a bit unfair. As humans do mature at different
rates. Still, it can be a shortcut, as maturity is usually hard to
know.