I like using leverage like this in the accumulation phase.
Assuming you had the money to purchase cash and made that decision deliberately, there is no risk beyond the fact that you might not get returns that outmatch the rate you're paying. A greater return than 1.9% is a quite decent assumption, IMO, so it's worth taking.
Probably no reason to jump through such hoops once you have enough (just as doing credit card balance transfers are eventually pointless), but during the accumulation phase, if you're buying the car anyways, it seems like a great move to me.