Agreed. Not an effective visualization. A bar graph would be much better.

Is very clear to me, just hover your mouse, my only issue is i think the graph could be bigger, but i think the graphic is very communicative

I don't have a mouse. How do I hover on a touch screen?

Tapping various parts does show and hide numbers, but I have no way of telling if those are the numbers that hovering gives.

It's clear once you interact with it, roll all over it, and thoroughly investigate it - all behaviours that get in the way of doing what it SHOULD be doing: showing me the data.