Some great footage and examples.
I don't agree with what he says though re shuffles for the most part.
Footwork is about balance yes, but it's also about being off balance (off centre of gravity) and still being balanced. I don't care what anyone says.
Take Ali for example. He had a innate ability to pull his head back off the line and still step around/balance and maintain balance, then either get away or counter. I've never really seen anyone else be able to do that.
Or take Pernell Whitaker, he could pivot, slip, step from his torso at a 180 degree angle.
Now you can call the above kinetic awareness, evasiveness, balance, agility, flexibility, whatever. But it's also deft footwork off the backfoot and front foot to be able to do it.