You could be right but it's an interesting method originated by the police who found it had advantages other than extending clutch life. it decreases it's life now.
I'm intrigued. In my formative years, and for reasons I can't for the life of me fathom, I regularly spent periods seeing how long I could drive the car (manual gearbox) for without using the clutch at all.
Of course changing up through the gears was relatively easy, a blip on the throttle and slip her in nice and easy, but firm, changing down took a bit more thought with the throttle but still do-able without crunching.
I never quite achieved pulling away from a standing start without using the clutch and probably stripped a few teeth off the cogs and buggered the synchro trying.