Losing your card at home is a pain in the backside. Losing it while abroad is a complete nightmare! You do NOT want to be in a foreign country with no money and no way to access money.
You should always have a few different sources of money. I personally have around 7. These are:
My primary payment method is Starling. It allows me to make purchased with no transaction fees, get real time spending alerts on my phone, and control the card with a smartphone app. (e.g, I can lock the card in a few seconds if it is list). My Revolut card is basically the same thing. I like to transfer most of my travel budget into these, split between them.
My two credit cards are there just in case I need them. Especially useful for any large purchases I might need, like a new smartphone or emergency flight home. They give good protection, even with the transaction fees.
The debit card for my main bank is also there just in case I need it. I can pay and withdraw money from ATMs with it, or a fee.
A smartphone with Samsung Pay (or Apple/Google) on it is another backup option, as a last resort if you somehow lose all the above cards. Can't withdraw any money, as far as I know, but It can get you train tickets or some food when you need it.
The important thing here is to not put all your eggs in one basket. Your wallet may be lost, your backpack may be lost, your suitcase may be lost, but you'll probably not lose all of them at once. If you do, then good luck! But realistically you'll probably just lose one, if any. So split your cards between them. Two in the wallet, two in the backpack, two in the suitcase. Try to hide some if you can!