Don't get me wrong, I am all for fully-mechanical parking brakes and am also wary of the electronic ones. Especially the "smart" ones that that automatically disengage when the computer thinks that's what you want, those are straight up dangerous.
But I've seen the mechanical ones fail in all sorts of ways. It's something you have to keep track of and occasionally maintain.
Right now I have one of the foot-operated ones and the bracket is bent enough that sometimes the catch doesn't engage on the first try.
Once I saw the chassis screws vibrate free on one of the center-mounted ones, one day the driver tried to pull the lever and the entire assembly just lifted off the floor.
My favorite though was in a bus, the valve for the air brakes fell to pieces when the operator was trying to let passengers disembark. She sat there with both her feet on the brake pedal while everyone got off and had to go straight to the shop.