I mean, practically, if someone tells me they're bi or pan, it doesn't really change my view of them. Like there's not really any practical difference insofar as something I would need to know to treat them somehow. Like if I'm trying to flirt with someone, and if I was a man, and that person I find out is a a lesbian, then I wouldn't. But if they're bi or if they're pan, it doesn't change that.
There is a difference, I'm not saying there isn't, and I'm not saying we should only use one if the two. I'm just saying the need for clarifying is overblown. If I'm curious why they picked one over the other, I might ask, but again, it's not super critical for anything.