I thought you were using an on-chain satscard from Coinkite. The bolt lnurlw cards can be problematic. Granted same problem a visa would have only they have checks for things like double billing and fraud. You're also relying on someone else running an lnbits or lnurl service and hosted wallet.

I believe lnbits let's you throttle transactions to any preset timeout you like. To avoid, their words, ass milking 🤣🤣🤣

But that would just delay a bad actor.