They could already easily track your face because your aunt uploaded a picture of you to Facebook and tagged you in it.
What they're trying to do here is connect your face/identity with your Discord account, so that they can more easily track down dissidents who say naughty things online through Discord.
Plus, no chargebacks.
If a customer gets cash from the ATM and then gives you the cash, they can't later try to claw that cash back by denying the charge.