In the System Icons section they have this tagline "Simplify icons for greater clarity and legibility." below an abstract icon of a so called ship - [https://material.io/design/iconography/system-icons.html?ima...]

Which I think is ironic.

Because if you see just that icon it's really hard to recognize what it is, I bet many won't see a ship it (at least I didn't). Only because of a realistic ship icon shown next to it that one realizes that it is in fact a ship.