If the car gets totaled and it’s my fault and If I had put the 10,000 as I originally intended to do, that money is still gone in that scenario so what’s your point here?
Assuming that you’ll always have cash in the bank to cover the “gap” between actual value and the balance remaining on the note is not always a safe thing to do. Your “free” money loan is costing you more than you’re getting in interest from having avoided a down payment.
Other than that, I suppose you’re good as gold.