Well I mean, if you look at it from the other side of the coin, being trans is still an integral part of a trans person's life. It defined them in a HUGE way, and its not something to be taken lightly. Some people might want to keep that special definition to the characters they make, whilst playing in a role where they feel accepted. Its a way of keeping an integral part of their personal history with them, while also having a character who is not being persecuted for the way they are. It doesn't mean they have to focus on it 24/7, but it might feel good to know you've created a character very much like yourself who isn't being targetted for the same things you are or could be experiencing.