Eyelids: Shape keys vs. bones: advantages and disadvantages?

As I’m still learning, I wanted to animate my very cartoony turtle’s eyelids with Shape keys.

No real problems (I’m used to vertices morphing in straight lines) but wanted to ask: what is the usual practice? Shape keys or bones? For a realistic eyelid I imagine shape keys would work better – for these hemispherical eyelids bones or just rotation might have been the better course.

Are there character animation tools that favor one approach over the other?