They don't play AAA games, they don't really do administrative work (and the times they do, Google Drive can help), and they can't really break it even if they tried.
You'd be surprised.
They can (and will):
- install crapware extensions
- allow notifications from random shady sites, which will then make them install more crapware extensions
- change their default search engine (and a lot of data that Chrome sends goes to the default search engine, e.g. keystrokes in the address bar)
It doesn't break the OS per se, but it still results in "my computer has a virus" support calls.
Don’t get me wrong: I am a big fan of Arch, but there are a lot of reasons to not prefer it over Ubuntu.
I think I can solve both of those with one stone..!
tl;dr - it's fine to snack on potato chips, but don't expect people to all want to eat the same thing. Variety is powerful.