Yes, you can analyze transactions for roundups from a linked credit card. All you have to do is add a checking account to fund those roundups.
Example:
Let’s say you add your checking account to your ChangEd App, and later link your credit card for us to analyze your spending and round up transactions.
In this case, we would round up transactions made on your credit card and make ChangEd transfers from your checking account based on the roundups you make with your credit card. We don’t want to be adding to your debt, right?