For humans death by dehydration is considered one of the gentler ways of dying. 7 days and your out.

For insects, it's a matter of a few minutes at most as the diatomaceous powder sucks essential oils and moisture. How much pain they feel I can only imagine it is close to nothing but the cuts they certainly will feel those.

Hopefully they don't evolve to resist that too and start to see them do lines like a cover addict with that stuff.

Yeah my pets would be my top concern but I see that it's safe to use, especially since it can be applied in places they won't be able to reach.