Well, I consider myself pansexual because I apparently don't care about gender. Different people use it in different ways. One of them is to stress the fact that they're attracted to not only men and women but more than two genders and that isn't really coming through in the word bisexual. Others use it to mean they are attracted more to the person than their gender aka being "genderblind". It might also depend on if you view trans people as a different gender, which kinda depends on what kind of trans we're talking about imo. To me, an ftm trans is a man and an mtf trans is a woman, so I wouldn't consider them seperate genders. But there are definitely other genders than just male and female and usually that already might make for example an agender person trans, because they were born with certain sexual characteristics they wish they didn't have. But - like many things - the distinction if someone is trans or not, regardless of their sex and gender is not something that can be assigned from outside and depends on what the person themselves feel. That's part of the reason I consider myself pansexual - I don't need to know a person's gender to find them attractive and I simply couldn't say if there is a certain gender out there that I couldn't find attractive. Granted, in day to day life I will mostly meet men and women (trans or not) so my sample sizes are a bit asymmetrical. But I definitely feel like "bisexual" wouldn't describe me well enough even though most people would probably have less of a hard time understanding it.