It’s simply not compatible. NIP57 zap mandates that the description hash of the invoice has to be the zap request note, whereas conventional with LNURL-pay invoices, it’s the LNURL-pay metadata that should be the desc hash. So basically a zap is not really using LNURL-pay, it’s just the same URL endpoint. So now all LNURL-pay servers has to also support this new propertary protocol. If we’re going to think long-term, this can have some seriously bad implications, as both LNURL-pay and NIP57 progresses and moves forward. But I can give you a clear-cut example: LUD-18 (github.com/lnurl/luds/blob/luds/18.md) also let’s you commit arbitrary payer identities to a payment (which is the primary goal of NIP57). But seeing how NIP57 takes precedence, there’s no way to use NIP57 and LUD-18 at the same time, which is just sad. To make things in the right way, zaps should’ve just used the already specified and established way to commit data, which is LUD-18.