Seriously, no joke, this system is as bad as DRM.
The trouble with DRM is that it essentially treats content owners as criminals, restricting their use of property they own, even when that use is legal.
I don’t know how it works outside of the USA, but you own that car, payments or not. A contractual defaulting of that property to someone else in the case of failure to meet payment does not make it any less your car.
Presume this: you buy a house with a loan from the bank, using the house you are purchasing as the collateral – a mortgage. What if the bank made it so that the key to your house doesn’t work? It’s not their house! Yes they loaned you the money, and yes it is within their legal right to create a contract that makes your life a living hell (by not letting you into your own freakin’ home) if you don’t pay. But it ain’t ethical.