Eh, lots of people are in jail in the US primarily due to their inability to pay court fees. Many because they couldn't pay the public defender fees.[1] Lots of cases where the accumulation of court fees dwarfs the financial costs of their original crime, and are punished much more for not being able to pay for fees than for their original crime.
Oh, and in some states they suspend your driver's license for nonpayment of these fees. This makes it even harder to work and earn money.
https://www.americanbar.org/groups/government_public/publica...
[1] Many wrongly assume that "the courts will provide one for you" means they're free. They often aren't.