“but it might as well be 850.”
In your situation it would not matter if it were 850 or zero!
That's what I told the wife - I really don't care what the score is - if I ever desire a loan (the last one I took was because it was zero interest for a period of time so I decided to go that route instead of buying the car outright) I have the luxury of twisting arms for the best rate or going elsewhere - when they know it's only a convenience instead of a necessity, it gives you a bit of leverage.
Not necessarily so. A good credit score also gets you better insurance rates. Just like with the bank; it shows the insurance company you are either responsible or not or just so so.