There’s also something called a “line of credit” which is basically a credit card with lower interest and no cash advance fee, but no rewards.

Obviously you don’t want to keep a balance on that either, but if you can’t fully pay off your credit card, you can at least save money by transferring the debt there.

My thinking is that it’s a way to avoid adding to existing credit card debt, and accumulate more net “interest free debt” so to speak, as it’s a separate pool from a credit card.

Yes, I know. But if one is going to have the debt one way or the other, I kinda see the logic.

From what I’ve found reading terms on some of these it’s fees baked into them that are pretty dang steep compared to interest if you pay them off immediately. Many then balloon once you get past some arbitrary point between 30-90 days. Might take a look at this to get an idea. I’ve seen these guys recently at a mattress store and googled a cost estimator to see how they worked.

Sounds like you're an ideal candidate for reeducation a tax payer funded visit to a summer camp.