Examples are often crucially valuable, not just for beginners. Some of them can inject in five seconds an understanding equivalent to an hour of reading the very-objective docs and experimenting. I'm thinking of some git doc pages. But it applies just as well to single functions that are very simple conceptually, but hard to describe clearly and briefly and completely.

The developer has time for neither or both. Once the productivity barrier for one has been broken, the other is a tiny extra effort. In that case, they must provide both, except in the small minority of cases that are exceptionally self-describing, where one (usually docs) is sufficient.