if u are confused, basically what im trying to say is that
uh
idk heres a made up example
say that nobody put their pronouns anywhere, and one day someone on here decided to come out as trans
because they wouldn't like being referred to by their old pronouns, they put their new one in their bio
and because nobody else put their pronouns in their bio, this trans person feels uncomfortable/ scared about putting them there because they are the "odd one out". hell, maybe some really bad people would harass them for it
so in the end, they could stop putting them there and just go back to being referred to by their old pronouns/ always be uncomfortable with their identity/ scared of being called "weird"
if everyone or at least a lot of people put their pronouns in their bio, trans or not, this person could feel completely comfortable putting their pronouns there because everyone else does it and they wouldn't be the "odd one out" or "weird"
(tl;dr- even if you dont care about people knowing your pronouns/ being misgendered putting ur pronouns in your bio is just.., a nice thing to do for others and will do u literally no harm)