"Ankle roll" is fine, as long as its Weight Shift doesn't roll the foot over and lift the outer edge.
On the backstroke, the left heel may lift, but the outer edge of the sole remains on the ground (as the weight shifts to the inside ball of the foot). Through Impact, the right foot similarly rolls (and its heel lifts). Then, the foot is dragged through by the Finish turn of the right hip (witness the sliding foot action of Hogan, Knudsen, Nelson, and so many more of the great champions).
I know that Jack Nicklaus rolled the edge of his left foot off the ground on the backstroke, then lifted his heel. But he succeeded in spite of that Balance disruption, not because of it.
Why did he do it?
Because that's what his teacher, Jack Grout, taught him to do (in the '50s).
And why did Mr. Grout teach him that move?
Because that's what his teacher, Henry Picard, taught him to do (in the '40s).
And why did Mr. Picard teach him to do that?
Because that's what Alex Morrison, the book guru and extremist theorist taught him (in the '30s).
That doesn't make it right, of course. But, that's the way it went down.
Position Golf is not Alignment Golf. Those who would play their best recognize the difference.
Four generations of women are gathered with loved ones for a Sunday night roast beef dinner.
The youngest is putting the roast in the oven when her fiance inquires: "Why do you cut the ends off the roast honey?"
"Thats what Mom always did, I dont know, go ask her".
To which Mother replies "I dont know go ask Grandmother"
To which Grandmother replies " I was taught to do that by Great Grand Mother , lets go ask her".
Finally Great Grandmother smiles and says; " Well we had a very small oven back in those days and I had to cut the ends off the roast so it'd fit."