Maybe I'm a bit old fashioned and not with the times but isn't that just biloveual (somebody with an interest in either physical love)? Why have such a silly label for it?
No, biloveual means you're attracted to male and female separately, panloveual means you're attracted to everyone the same way regardless of gender.
And genderfluid is when you feel like two different genders at different times, and yes it is real. Like, some people will feel male for a while and female for a while, or female and neutral, or any other combination, but it does happen. You switch back and forth and it's not something you can control or choose.