+1 for me, too. In this case, coming from XD. I think that a feature like Repeat Grid should allow repetition of any layer on the canvas. Say: you want to repeat a group of elements or a frame. This way, you could select any object inside a component and repeat it.
As earlier mentioned, there is also a request for a slot feature (arbitrary instance swap in components), where I think that a repeat grid could help big time. If, inside a component, you can repeat an object that happens to be instance-swappable, this could be really nice.
I do foresee some issues: what if you want to have one component to repeat, but any repeated component is the same variant? I think that the repeat functionality would be most powerful if it ships with the ability to override component properties per repeated instance.