He does mention it: by giving his sons a credit card, one benefit is that when they graduate college, Frank has essentially built their credit for them.
They are also often the best method consumers have to borrow money for many purposes.
(The only exception would be in a deflationary environment.)
Seems a bit like Trump supporters.
Although it has to be said a running balance is not actually a direct credit risk. It doesn't make financial sense, as you're racking up interest fees, but if you are safely managing your payments (no late ones) and your credit usage (a percentage of what your total available credit lines are) then it's not a bad thing for your credit score.
Not that I would recommend it of course.
The more you demonstrate your ability to manage debt (and you can do that by simply paying off your card every couple of weeks) the better you demonstrate your ability to do so. More data points, so to speak.
Of course if you can't manage that then that's data too.
A debit card won’t.
I had to explain this to a school friend recently as he has never owned a credit card and avoids loans - preferring to save first, then spend.
When it came time to get a mortgage he couldn’t get good rates - or a large enough loan - as his credit history was so lacking.
He was infuriated but I pointed out to him that it makes sense from a lenders point of view: they gave no record of him being able to manage debt responsibly.
So that’s one reason to use a credit card, though likely not any reason Frank would suggest (he’s going with their better protection and coverage)