Yeah lane splitting is foolish to me as well. The main thing is it shows the performance of this motor. Maybe it "only" has 82 HP, but it goes like stink. I kept wondering why he did not shift to 6th. I use as little clutch as possible to keep the shift smooth. Just a touch of clutch and she shifts like butter up or down.
I used to lane split in my college days but only when the cars I was going between were pretty much stopped. Spent the whole time looking at the front wheels of the cars as that will move first before they try to change lanes. Not sure if it is still legal but it was legal at the time so long as you didn't go more than 10 MPH faster than the cars.
That said, the guy in this video is lane splitting in a way I never would... seems rather dodgy to split between a car and a school bus upwards of 50 MPH.. things happen to quick.