Honestly, dollars are fungible. For less sophisticated customers, points which can be redeemed specifically for travel are attractive because people anticipate getting better deals than they end up with; but I'd be disappointed if that works well for the audience you're targetting here. Just make it a cashback %age based on the fees you get from the card network.
On the AML/KYC by regulation we can't rely on another party, we have to do our own :/
Ah, too bad. But even if you have to do your own AML/KYC paperwork, pulling data from Stripe should help with risk scoring, right? In particular, for those of us with unfunded but profitable startups.