Actually depending on how hairy you are you may have hair -

not joking - did you ask them why not the wrist? It's an ugly scar but apparently because it's the thinnest skin on the human body it does well as a graft - and there's no hair on the inside of your wrist traditionally. The only down side is they shave a few layers from your thigh to cover he wrist so two areas to heal - mine was from my wrist and so far so good.
It's not a bad operation - does take a but to recover. I am so glad you are having a bilateral done too - good luck!