Yep, it could be used for finding extortion targets. Just find someone with bad credit who also works for some sort of sensitive program, and now you have leverage over them.
They’re very particular about this; particular meaning polygraphs and agents talking to your family members. I know because I almost took a job like this (and know a number of people who have) but the pay and location were crap.
How much do you think legislative aides are scrutinized? Political party staff who aren't on the government payroll?