Heya. Trans woman here. Having both could be neat? Being trans is about who you are not matching your body, whereas futa is just functional hermaphroditism and doesn't necessarily involve any sort of identity stuff. I know I like futa stuff, but it doesn't have to mean the character is trans. It's a magic world, you can just have a girl with a dick who didn't have to deal with gender trouble.
To tack on just as someone who likes futa - futa and trans definitely aren't the same thing and people requesting futa I assume know what they're asking for. I personally prefer futa over trans (or shemale if we're speaking of the...I guess fetish specific term - IMO trans is the lifestyle and shemale is the fetish, but have seen them used interchangely and honestly don't know which is more 'correct'), as I like futa on futa esp or male on futa, and dig the vaginal sex. I have no issue with trans/shemale but my specific tastes are futa, and some people's will be trans/shemale. If you really want to get into the weeds there's also full package futa (futa with penis, balls, and vagina) or just futa with penis + vagina. That one for me really depends on implementation, some do it weird, but a vagina hiding under a big ol pair of balls can be good.
Bit longer than I meant, the tldr is there's definitely a difference in trans/shemale and futa, and most who care about futa have a preference on what is considered futa or trans/shemale. I personally would be just fine with both, but appreciate the differences.