No magic, it’s just that the effect is small so you need a long strip to get enough motion to tilt the mercury enough. Coiling it lets it fit in the little box on the wall and also ensures you get a tilting action on the mercury switch.
Honestly, the primary feature of modern fast elevators is that they accelerate at all. Older elevators are literally a cable on a drum with a motor that turns on and off. Below a certain top speed, you don’t need to accelerate and decelerate. Think about you garage door opener, for example. It doesn’t have an intentional acceleration or deceleration curve. It just goes. However if your elevator is fast, you need to have an electronic controller to accelerate and decelerate at both ends so that you don’t terrorize the contents-I-mean-passengers and also because it’s easier on the equipment. No fancy PID or anything needed though, just a motor controller with an accel/decel curve in it. Most things in the modern world are simpler than most people think they are, in my humble experience. However they are definitely smug.
