I cannot get the movies to work, but he does say that this is not meant to replace water changes - but to supplement them. He changes water , using this machine and then, AFTER changing the water, continues to filter and clean the rest of the tank with it. What he is saying is that if he removes a lot of the waste BEFORE it is transformed into nitrite/nitrate, then he has less nitrate to worry about in future water changes. This is true.
As far as I can tell, though, it is merely a slick design for a power water pump with a nice filter included - such that you can filter as you suck your way around the bottom of the tank rather than just use the removal of water/waste to clean a tank. That is a good idea - but nothing new.