If they're still using debit cards and cash, it seems their same-aged peers believe the hype that credit cards are inherently evil. When I was a student not so long ago, some of my peers were disgusted that I talked about credit. They told me it was evil and it would ruin me. They told me they were smart to only use debit cards. If none of us grew up, we'd also think that the hot stove, circular saws, and other inanimate tools were also inherently evil just because we saw other people make mistakes and get hurt.
OP, I think your heart is in the right place. You want the best for your kids and extended family. That's great. But all they're learning right now is how to shut out their dad and uncle. If they're old enough to apply for credit cards, they should also be mature enough not to spend their last dime every time they get it. That's far more important than using credit cards for purchases. My parents helped me to understand saving by the time I was 5 -- and I have my first savings account passbook to prove it!
If budgeting and saving is the 101 course, revolving credit is the 201 course. Without good habits, adding credit is not a good idea. It sounds like they all flunked out of 101, so they should've retaken that before moving to 201.
If I were in your shoes, OP, I would turn your nieces' and nephews' cards over to them, and work with your own children on the 101 course. If they have subscription services to put on their cards, even better, so the management of the cards could be completely automated, thus dropping the 201 course. Work gently on spending habits by asking questions like "how are you going to move out?" or "how are you going to buy a car?" so they feel like they have some skin in the game of saving. Once they are able to control spending, then it's time to discuss the advantages of credit cards in the 201 course.
This is about motivating them towards the advantages rather than telling them what to do.
Best of luck, OP!
