You can miss out of potential dialogue and facets of the characters though when they're playersexual though.
Cassandra in Dragonage: Inquisition is my first thought of an example. You can pick the 'romance' choices as a female and eventually, it comes to a head and she talks to you. A businesslike, harsh, stoic and proffessional person is awkward, nervous even when she explains that she's been pretending not to acknowledge the flirting and wants you to stop because she's not interested and you're clearly not getting the hint. People aren't 'baseline bi' in real life, but this is a game with elves and magic and wizards and dragons and brain-eating squidpeople so while I certainly would prefer a character to be a set sexuality (or they think they are-imagine the writing potential for an npc falling in love with what they think of as the 'wrong' gender) but... eh. The simple fact for me is; I don't care enough to howl in outrage over this, I would just like people to acknowledge that it sandblasts down a potentially interesting part of a character to bland nothingness.