Curious which/what dealerships or car mfgs are onboard with this or driving this development. I think the biggest issue is ensuring some level of human review and shorting a workflow at any given step before the purchase itself.
There are a lot of shady dealings and scammers around auto sales... Having certain assurances and safeguards is definitely important here.
Disclosure: I used to work for a used auto classifieds site, and own a domain I'd intended to use for that same purpose.