http://waffles.i2p/blog/familiarity.html
Same with running games outside of steam. Doable, but not super super intuitive. Heroic Launcher, Lutris, etc. make the task a bit easier but not always perect. For the Most part, though, you can give a user a Chromebook and they'll be reasonably happy (provided they didn't want to hook up a cd player or anything).