A genuine self-custody head-to-head: both cards spend on-chain from a wallet you control, so neither asks you to park your balance with an exchange. The split is which ecosystem you already live in.
The MetaMask Card spends from your MetaMask wallet and reaches a slightly wider set of markets, with a higher cashback tier on its Metal option. Gnosis Pay spends from a Safe smart wallet and ties rewards to GNO holdings, with a strong EU footprint. Both charge card-issue and FX fees we mark as unconfirmed until verified.
If your assets already sit in MetaMask, its card is the natural fit; if you prefer the Safe smart-wallet model, Gnosis Pay is the match. Either way you keep custody — which is the whole point of picking one of these over an exchange card.