I am on a mobile device and I consistently find that my finger is not precise enough to draw a path; it kept complaining about path “not quite right” where my path just touched the wall a little bit. And when my finger literally obscures the screen while drawing, it essentially means I have to memorize an entire path before beginning.
This requires significant spatial thinking skills and short-term memory for a human and it is absolutely unfair for a human to expend that much cognitive power to access a website.