Nice but personally it seems completely unnecessary. Leave wire (or thread) at tail. Tie in hackle at head and wrap back to wire. Tie off with wire and wrap wire up to eye area. Serves the same purpose, is easier, is faster, makes the hackle just as secure, and actually looks better than the fly in the video which has the thread as the body, or so it appears.
Not to hijack this thread because one purpose stated for this type of technique is the protection of the hackle. So I have 2 questions to ask, 1) 'How many of your flies(the ones you've personally tied, not bought) have hackle that's come apart due to the teeth of a trout?' 2) 'If you've caught some trout and the fly's hackle has came apart, are you really disappointed in that fly?'
Personally, my answer to #1 after more than 40 years of fly fishing is, I can count the number of flies where the hackle has come apart on 1 hand. And #2, no I'm far from disappointed. In fact, I'm ecstatic and happy to have sacrificed a fly to the fishing gods. I'm sure that I have more than enough of any pattern, at any given time, to replace that abused and torn fly.
Allan