The rats that the cats are keeping out of the stores are a much larger source of pathogen transmission to humans than the cats are. Not only do rats carry many more dangerous diseases than cats, but both can also transmit toxoplasmosis to humans. As it is transmitted through contact with feces, from which of the two are you more likely to encounter feces spread all over the store?

So, while I actually find both rats and cats endearing, I'd take the cats over wild rats in the stores any day.

I think we owe our civilization to cats - without them we would have never been able to stop being hunters-gatherers and settle into agricultural society as having food stores would have been impossible due to rats.

And Black Death, owing to Church persecution of cats, is another great illustration of cats' role.