Ive never been asked for that by restaurants but I have been asked to approve the check for other type
jobs, minimum waged and not even interviewed--asked for it to even apply!
I suppose it depends on the business.
You've had multiple interviews, so they're obviously genuinely interested in you. But whether they're asking
for the credit check because its they're standard policy at this point in the process, or as a "tie breaker"
between you and one or more other applicants is hard to say. I don't see anything you can do but comply
and see how it affects their interest in you. Either that or just tell them
"well okay, but I do have some derogatories on my credit--is that likely to affect my being hired here?"
That serves two purposes--the obvious information you'd get, plus it shows them that you're upfront and
honest about whatever they want to know--not hiding anything.
In the end, I find it nonsensical that they would rule out an applicant based on poor credit--obviously
you're seeking employment to improve that situation!