The reason you use them is that they allow you to not leave the home row. So say you're writing something and need to move back and delete a mistype, it's much faster to do that with C-b C-b C-b backspace <letter> M-f than moving your right hand to the arrow keys and moving it back to type the letter and then moving it to the arrow keys again.
Now, lot's of people can't be bothered to take the time to learn them. You need to go through the Emacs tutorial and perhaps spend a day or two getting used to them. That's all it takes.
Similarly, most programmers I personally know can't touch type. That takes a few hours of practice with a fun, gamified touch typing program for a couple of weeks, and then you have set part of your mind free. But people can't be bothered.