I haven't compared them, but Transferwise account and card are solely for travel / forex use and they are specialised for that. There are no other monthly fees. There's the FX rates, which were 3rd best of the kind last time I checked and when converting currency or withdrawing to your own bank account, there's a £0.50 charge depending on the currency.
It's a Mastercard, but it's not a credit card, it's a pre-paid card, so you need to have the funds in your currency account to use it for anything. The clever thing is that if you have multiple currencies and you run out of one, it should convert from others (if you had balance on other virtual currency accounts) to cover what you needed to spend.
This is why you can't compare this with high street bank issued debit cards with low or zero FX fees.
You can compare TW card with Starling, Mondo and the like.
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@edh said, it's good to have a credit card to use as guarantees and also to have a backup card in case the main one doesn't work.