system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are credit/debit cards not coded with the card type?

Frequently when I purchase something with my credit card, the machine asks whether I'm using a credit or debit card.  I've even chosen the wrong one before out of curiosity and the transaction went through just fine, and showed up normally on my statement later.

So if it's going to work regardless of which button you press, is there a reason this information is necessary in the first place?  And is there a reason the card type isn't just encoded on the magnetic strip or chip?
gpt
It seems you misunderstood. It's not that the terminal is stupid, it's because the terminal is smart. 

The reason some payment terminals ask you the type is because your card is of both. It has credit side which means your bank pays for you and then sends you a bill later, and debit side which is attached to an account with your own money and no one bills you for that transaction later. The system is merely giving you the choice to select which part you want. 

This is quite typical in Europe.