Yes, they're commonly used as "starter" credit cards, to increase credit score. I presume they also come with the other benefits of a credit card, such as the amount of security deposit required when renting a car, as well as fraud and chargeback liabilities and timelines.

It makes sense as exactly that. You show the bank that you can manage a float. When you’ve demonstrated you have the executive function to do so, your score goes up.

I've never used a secured credit card, and I'm with you that it seems ridiculous.

But I think a more honest question is: Why do people do this?

I'm willing to give folks the benefit of the doubt for being smart and rational. So genuine question we should be asking ourselves (or them): What is the appeal of a secured credit card? Is it really just about the credit score?

I did this when I first moved to the US, and had zero credit history (which the system considered to mean "high risk"). The entire point is to improve your credit score.

It is just for improving very low credit score, for people not eligible for regular credit cards.

You get the money back upon closing the account.

With no interest, and they typically take months to give the money back. They get to invest the money for that time, and you don’t. It’s an outright scam, but you have to have a credit score so whatcha gonna do about it?