While I hate that it's like this, you're leaving money on the table.

Currently you're keeping money in the bank accruing the bank interest to occasionally pay for stuff.

With a credit card you would get various bonuses/cashback/gameified returns by owing them money, and it costs you nothing as long as you pay them back once a month interest free.

If you however slip up/miss a payment it will cost you a lot.

Both cases suck, but the latter saves you money if you play that game.

That's from a EU perspective. From a US perspective you also require it from a credit score perspective, which EU thankfully hasn't adopted... yet.