There have been times where I've wanted a groundsheet. Namely, the sharp, sandy gravel of car-camping campgrounds like the ones in Acadia National Park, for instance. Anywhere where rolling in my sleep can pull the fabric over sharp rocks. The Eastern Colorado Desert also stands out, especially in Fall when the goatheads are out.
In that case, I use Tyvek. There's a lot that will quickly pierce polycro that wouldn't get through tyvek. It's one of the few materials I put a lot of trust in for abrasion resistance.
But yeah, other than vegetation-free, desert or gravelly conditions, I don't bother.