When Stripe eats his lunch, he'll just find something else to simplify/solve they offer that's too complex, and probably still make money. They may even try and hire him as a product manager or something.
You’ve got a good niche and I have to admit I’m envious of the position you’re in—that level of autonomy seems rare.
It’s also a stupidly great idea for non-technical trade and craft shows. No infra or complex setup needed. Smart. Well done.