And you can bypass a seatbelt warning by just plugging in a buckle without the belt, but most people don't bother. It's not worth the inconvenience to circumvent, so it still has a positive impact on safety.
A shocking fraction of people will simply ignore the seatbelt beeping for the entire drive
Seatbelts are actually heavily enforced around the EU, most people would rather just belt up than pay the fine.
Go in a car from 1970 and try the seatbelts.
I can see why people didn't want them.
I too would rather not have a stiff blade like plastic meterial nearly cut my head off everytime the car breaks.
By comparison today we have luxurious silk strands that don't pinch anywhere.