Hover vs Highlight activity

Hello all,

I was wondering why Hover activity can access unvisible elements on the page while Highlight activity can’t?

Say we have a list of 100 items on the single webpage and only 5 items of 100 are visible.
If we use Highlight activity to access for example 21th element, robot will crush giving the error The UiElement is no longer valid whereas Hover activity will literally scroll down selecting each item, working like charm.

What is the difference between those two activities?