> E.g. The weirdest part of it (after driving an old car for the longest time) was they explicitly tell you not to have gas-station attendants check your oil for you. If you're leaking/losing oil, the lights will at some point come on and prompt you to take the car in for service.

Why is that weird? It's a pressurized system with plenty of sensors, you are certainly better off following the data than a gas station attendant (which itself is an old fashioned concept in most places).