I was referring to the triple buffering, full use of GL for rendering and better vsyncing when I talked about graphics changes, not GC stuff. That was separate and also makes things smoother but it's unrelated.

Deferring pauses is quite realistic for many kinds of UI interaction and animation. If your animation is continuous/lasts a long time and requires lots of heap mutation then you need a good GC or careful object reuse, but then you can run into issues with malloc/free too. But lots of cases where you need something smooth don't fit that criteria.