I've made my feelings clear in multiple posts
I do think they are basically the same thing, and the hang-ups with people trying to say that bisexual people wouldn't be as open-minded, or are caught up with very concrete notions of what gender is, is hugely offensive to everyone who's ever identified as bi in the past.
The whole adventure in becoming more open-minded and laissez-faire when it comes to sexuality and gender is just fraught with tarnishing older labels.
I really don't care if someone chooses to say they're pan instead of bi, I just make a mental note of "...okay so they're bi, then" lol.