To explain Max Behr's ideas on the "line of charm" best, I think, is to properly call his concept the "line(S) of charm!
Certainly his ideas are to give the golfer what he called "freedom of expression" by creating multiple options for him to choose to challenge him in the way he perceives best for him!
But Behr believed the best and most multi-optional way to create "lines of charm" was to take away from the golfer what he called the "line of instinct" by placing a hazard feature at that point--ie, "line of instinct"! That point very well could be something like the middle of the fairway at the exact and ideal point where the golfer might instinctively want to hit the ball.
Taking away that point would logically induce the golfer to choose to hit the ball short off, left of, right of, or over that "point of instinct" (where the architect had placed that hazard feature) thereby creating for the golfer what Behr called "line(s) of charm".
Behr, in this way, believed, in a sort of "glass half empty/glass half full way, that a hazard feature (placed at that "line of instinct") was not really supposed to be viewed as something that was "penal" but something that was supposed to act a "sentinel" for the golfer to challenge it, to come as close to it as possible in some way for the ideal position for his next shot!
As hazard features (particularly bunker features) are architects' primary design expression to create strategy in golf Behr believed they were ideal to create his philosophy of "line of charm"!
As anyone could imagine, to create "line of charm", width was valued and because of this Behr also did not really believe in the use of rough in golf or it's architecture!