Why they don't need to be wet?

To activate a touchscreen they simply need to have capacitive properties.

Interesting, it sounds like they should try to invent something that works in similar way to nerves on the skin as you can feel slightest touch regardless of moisture.

I remember one elevator button was a large metal bulge, that didn't get pushed, but instead did a little electric jolt to my finger (at a very small distance between finger and the button).

Here you can see it on 0:23 of video tour: https://marketplace.vts.com/building/400-capitol-mall-sacram...

Maybe multiple accelerometers plus machines learning could improve tao detection?