Likewise, if you work in a job that has access to ‘company secrets’ someone deeply in debt would be more easily bribed to give away that information. That’s the same logic as to why the government checks you for clearance jobs. It may not be quite as life and death, but it is very important for the company. If KFC hires someone who sells their secret blend of herbs & spices to pay off their credit cards debt (a silly, but relevant example), the company is in trouble.

Auto insurance is more of those ‘who knows why but it works’ things. People with high credit scores tend to have lower rates of claims. It could be because they have better financial resources and won’t claim as many little things. It could be because someone who is responsible with money is more likely to be ‘responsible’ with other things in life, such as driving. It could be something else, or it could be some combination of all of them. It’s not really ‘fair’, but it works and that’s why it’s widespread.

Once insurers figure out that low credit scores correlate with poor insurance risk it is certainly understandable that they want to use that factor in their decisions. It may not seem “fair.” Many things about insurance are not fair. Plenty of young drivers are responsible, safe and accident free. But since many people of that age are irresponsible and accident prone all young people must pay more for care insurance.