Sometimes, they have double meanings. HotelTonight's logo is both an "H" and a bed. Clever icons look good and represent what an app stands for. Like Duolingo's owl, "Duo." Because owls are wise ...

However, the icon Safari currently suggests for Twitch is their old logo, which I don’t think looks as good as the new one. But I was able to fix this using Federico’s “Save App Store Icon” shortcut.