Historically it was to stop home bodgers just letting it drain into their gravel drives when changing thermostat/ water pump etc, then filling with neat h2o,
Stop pollution, and stop corrosion in the engine
Surely there are a lot of vehicles out there of any make that don’t need a spanner, or a fix between services, problem is, they don’t show themselves unless they’ve been in your possession for a few years!
Failing bush in a shock absorber, bent shock, broken or soft gearbox/ engine mount, centre tunnel just touching gearbox, the list goes on, get underneath and start looking , anything shiny ( rubbing) that shouldn’t be?
Do you notice if the heat plugs light is working in dash, it’s unlikely to engage starter until it’s run its heat cycle , the colder it is, the longer the heat cycle