Depends on the game. I remember in Rainbow Sex Vegas you could scan your face onto your character. It was a little strange but honestly, pretty cool too. If AI could capture my mannerisms and make it more believable that its an accurate representation I would do it in like a GTA Online or other games that are representative of my environment.
For example, GTA is accurate, but Dragon's Dogma is not. I don't have a British accent and I imagine I would sound very odd with one, though I do appreciate the accent itself.