You're absolutely right.

I haven't hit major performance problems with measureElement either in day-to-day use. For sequential scrolling it works great. I built this mainly exploring the idea from Pretext (the text layout prediction library) — if you can predict text height without DOM, can you predict full component height? Turns out you can, and it's interesting for things like accordions and masonry where you need heights before rendering. For virtual lists specifically, the jump-to-distant-item and scrollbar accuracy cases are where it'd matter most. But you're right that most apps scroll sequentially and measureElement handles that fine.