If I have bad credit in the US, I don’t get locked out of riding the bus

You might!

I know a lot of areas are switching to digital-only bus fares, and those, of course, require a bank card or credit card...

Guess what can lock you out of getting those, and thereby, riding on the bus?

There’s also no credit-score check in the US for job applications, so no, it doesn’t “lock people out of finding work.”

Do you live in the US? Lots of employers run credit checks as a part of their normal background checking. I've see people fired for bad credit scores.