You've got to spend money to make money, or so they say. The hidden addendum to this popular phrase is that it's usually other peoples' money that you're spending in the process. One of the craziest things about being a responsible adult is that you're generally considered more trustworthy financially when you have some (well-managed) debt.
It shouldn't make sense, and often it doesn't seem to. This was certainly the case for one person's credit score that went viral on Twitter recently. They complained that after paying off their vehicle, their credit score had dropped from 'Exceptional', to 'Very Good'. It comes as no surprise that many people had a few choice things to say about this system where being debt-free is seen as something to be suspicious of, as opposed to celebrated. Good credit score or not, I guess fewer people can make the investment of a mortgage these days anyway.