Well, for me the difference is that a bi person is attracted to multiple genders or sexes and a pan person just doesn't care about gender. I am certainly panromantic as a person's gender is just unimportant to me because in a relationship I'm looking for someone with a compatible mind. For physical attraction it is much harder to determine. I still consider myself pansexual because I think a body can be physically attractive whatever gender or sex the person inside it might be. But there certainly are some classically male or female attributes that attract me. I don't know if that makes me "less pansexual" or "more bisexual" or if that's just how physical attraction works for people who don't consider romantic attraction and physical attraction to be the same. 🤷