Bisexuals are salt water and pansecuals are freshwater. But fr from my understanding bisexual started as an exonym (originaly it meant something like hermafroditism but later it became about orientation), and since bisexual people have always been subject to erasure they latched onto it. Of course this term came to existence when the academic view of gender was binary so way later people wanted to update the label to reflect the change in paradigm but a lot of older people had become very attached to the laber and refused to change it and then people tried to rationalize differences but they are so subtle that imo is an exercise in futility.

I use both , but use pan online where people are more likely to understand me and bi irl cause for a lot of people the label pan feels completely alien.

You can only be bisexual if you are from the bisexual region of France, else you are sparkling pansexual