Hmmm. I'll have to check the old posts again because I seem to remember there being a difference between the lagging clubhead takeaway and float loading.
I see float loading in Miller Barber's swing, but the lagging clubhead takeaway is more Bobby Jones or Greg McHatton - brushing the grass and then cutting it off at the roots per Confessions of a Former Flipper.
Sorry I seemed to have confused something. No nearer knowing why it might be advised for someone with a hook. I have had some success with it, but still hit the odd low left. Wondering whether to persist.
Based on how it feels, it seems to keep the clubhead outside the hands in the takeaway with the clubface pointing more at the target. This seems more up the wall (the book of Brian, 3:11).
Compared to my normal swing, this feels more shut to begin with. However, it then feels more open at the top! It is as if the momentum of the clubhead doesn't give my left thumb any option but to be in a more supporting position at the top, instead of more to the side with the wrist arching.