But I found a bug there: you cannot send zap from BBW to user with a BBW Lightning Addresses.... https://github.com/GaloyMoney/galoy-mobile/issues/1344
I tested Bitcoin Beach Wallet (a direct apk file from https://github.com/GaloyMoney/galoy-mobile/releases) and there are ZAPs work! So the BBW supports NIP-57! It means that Salvadorians can use (and USA and EU citizens) this wallet for ZAPs (with ZAPs stats!). Cool!
Discussion
My problem was that I was testing with myself and trying to send sats inside the same BBW wallet account. As it turned out, he does not allow this to be done, which is logical. Another BBW user can send sats to another BBW user without any problems.