I agree with you but I think the idea of having a credit card just for online stuff is to limit the ways in which someone can get access to any information about your credit card, like the last 4 digits. For example, someone who finds your credit card receipt at a restaurant would get the digits of a different card and couldn't get access to your AppleID.
It's actually a good idea. I'll think about doing that…
It's actually a good idea. I'll think about doing that…