When I say hurt/uncomfortable, I mean more like, "OW!" or when it's so bright you have to squint or look away. Spots-in-vision doesn't really bother me. I just realized that the statement ended up being more complicated than it should have... lol. You've basically got the idea though, it's personally the highest power I would use for pointing.
But with that said, I still wouldn't use anything above 5mW for presentations, just because you never know what will happen with a lot of people. Then there might be a reflective thing you hadn't counted on, and when you only need to see the dot, IMO 30mW is just plain too bright.