Even if they can prove sufficient steady income, if they don't have a good credit rating, there's a good chance they are unable to get a bank loan, credit card (or additional credit if they have a card already), and perhaps not even a small overdraft.
I can't speak for the US, but in the UK, even "payday lenders" who charge >1000% APR rates will no longer lend to someone with a poor credit rating.
On top of that, for someone who isn't used to it, and who already lives on the edge of what they can afford, "thousands", probably at high interest, is a big loan they may reasonably worry would put them into an unrecoverable debt spiral.
But credit rating counts for a lot.
Even if they can prove sufficient steady income, if they don't have a good credit rating, there's a good chance they are unable to get a bank loan, credit card (or additional credit if they have a card already), and perhaps not even a small overdraft.
I can't speak for the US, but in the UK, even "payday lenders" who charge >1000% APR rates will no longer lend to someone with a poor credit rating.
On top of that, for someone who isn't used to it, and who already lives on the edge of what they can afford, "thousands", probably at high interest, is a big loan they may reasonably worry would put them into an unrecoverable debt spiral.