it's "obvious" until you learn that most games (with way higher perf requirements than anything else) are immediate mode rendered. as with everything it depends - in this case, on how much usually changes, and how nested your data is (DOM trees are O(n^3) to do proper retained mode diffing, whereas full rerendering every time is O(n))

React's reconciliation bridges this - immediate mode programming model, retained mode commit model, with key-based bailout to solve the O(n^3) problem. There are reasonable disagreements as to how necessary this is, of course.