are safewords really necessary? hear me out

ok, title is a tad clickbaity, and i'm sure this isn't anything that hasn't been asked before.

but i wonder in what circumstances are safewords truly necessary.

for instance, i don't feel like me and my partner need one. we can tell just by our body language/facial expression whether we need to stop and check in. and also whether a "no" is a fun no or actual no.

i have a hard time seeing a circumstance where you can't just look at your partner and be able to tell whether they're into it.

it makes me wonder if a safeword is, perhaps, for people who don't actually want to stop or care if their partner isn't into it.

but my gut instinct is that this is a very dangerous assumption to make. perhaps my partner and i don't play with situations in which we genuinely need a safeword.

can any other kinksters give input? or does anyone agree with me?

edit: really love the discussion going on! :)