It is OK to ask questions about games under playtest; we facilitated tons for the D&D Next Playtest as you remember. (Just don't break your NDAs if you're under one.)

*That particular question* wanted a comprehensive edition comparison, which seems like too much to ask during an unsettled playtest. I'd say we should hold off on edition comparison questions for games under playtest, but that's only my subjective judgement at the moment: the community may disagree and so might my fellow diamond moderators.

I think we should be using a [tag:pathfinder-2e-playtest] tag for playtest materials. Once the full game is out we can use a [tag:pathfinder-2e] tag instead, and people can ask about the finalised version there without potentially getting cruft from the playtest filling the tag. We discussed the idea of doing something like that for the D&D Next playtest (https://rpg.meta.stackexchange.com/q/6554/1204, https://rpg.meta.stackexchange.com/q/3530/1204) and only afterwards realised the utility of having a [tag:dnd-next-playtest] tag, and I think we should be doing that in advance this time.