Where I'm at you can check a car's safety test history through the government along with mileage.

Srrvice history is another matter and having something accessible would be great, especially for imports. Places like australia and the uk have tons of used japanese imports with no history.

Some cars are serviced but have no documents to prove it. But i don't know how you prove blockchain entries as being true.

They can't be changed of course but what stops them being lies to start with?