Great question!

We live in this crazy time where the legacy system and the bitcoin network are running in parallel. Today, with Oshi, someone can effectively pay with dollars over the lightning network (Strike) for goods and services and receive bitcoin 'cashback' (don't say that too fast or you'll wake up Roger Ver). This isn't scammy to me. You pay using dollars, and get bitcoin-back.

The scammy part is traditional cashback, whereby you're paying with dollars, and these debit/credit cards/rewards systems are basically just keeping your change under their 'INTRAnet of money', or walled-garden platform. For the longest time, if a business was offering 3% 'back', that would be called a discount. They would simply give you 3% of that item back in change. Today, they want you paying full price and locking in your rewards on their platform. Your change.

Furthermore, these businesses are passing down the payment processing fees (which are higher than the reward you're getting) to the customer. So when you earn these 'rewards' from your credit card company, you're really just having fun staying poor. The business is going to charge you an extra 3%+ to use your card, and the bank is giving you 1-2% 'cashback'. You're still losing 1%! Where it gets interesting is that if you use cash only, you're still paying the higher cost (unless they have a pay with cash discount) as if you were swiping your card, but getting 0 rewards back.