Metal Pay is a custodial wallet. A custodial wallet is similar to a bank where another party takes custody of your assets and allows you to access them with id verification (username/password). With Metal Pay, any crypto you purchase is securely custodied by Metallicus and registered to each user on a ledger. If you forget your password or lose all access to your account, Metallicus can assist you to regain access to your funds. 

Other wallets like WebAuth are non-custodial wallets. With a non-custodial wallet, the individual is responsible for the custody of their own assets which means they must store their private key and/or seed phrase in a safe and private location. If you lose your keys you lose access to your cryptocurrency. However, you also have full control of your assets and can hold or transfer them at any time you wish without the need for an intermediary.