Most of the time they are lightweight plastic shells and will crumple before causing any extra damage.

Because actual lube works better?

One other fantastic option is to be holding something and to drop it as a safe word. Requires no mobility other than fingers

You are not wrong. But trans folks can be a lot more sensitive around language use sometimes. Misgendering ranges anywhere from annoying to hurtful to being an actual verbal attack. So their skin is often less thick for gendered language.