Zero.
If you have one penny in credit card debt you are an economic moron and your silly opinion on economic matters is worth the same as a roll of used toilet paper.
The notion that someone might carry credit card debt for legitimate reasons appears to be beyond your understanding. Having said that, I'll stack my "silly opinion on economic matters" up against anyone else's on this site.
The notion that they might do crack cocaine is also beyond my understanding.
Are there any taxes you don't like?
Credit cards are a wonderful tool if you know what you're doing and how to play the game.
I carry credit card debt - usually 0% promotions for a year. Basically, that's free money. I take that money and invest it in mutual funds where I earn interest. When the card starts to charge interest, I pay it back IN FULL.
Oh, I also have another card where I get 5% cash back on groceries, gas, and drug store purchases. I pay that in full every month before any interest is applied.
Sometimes, interest is only 1.6% or 3% promotional for things like balance transfers. It's not hard to earn better than 3% on many investments. Sometimes it's wise to carry credit card debt and let your money work for you.