Because this is a tight while loop we would expect iterations to reach a high number IF the whole cell was only reevaluated when the value of stepped changed. We can see iterations stays low though, indicating the cell is restarting every time the static promise is returned.

Yep, that's what makes "slowing down" unfeasible if you have any generators (including viewof) as dependent cells - which, I'd think, is the more likely case. The section "Trickle-Down Time" below should make this more clear.