While I agree that this is generally true, there may be other times when walking can be useful. For example, suppose I wanted to book a AKV CL and the 11 month window opened on the same day reservations began for BLT and THV. I might be very tempted to walk my reservation by beginning the booking a day early rather than join the massive phone queue, but only if I had enough points to book more than 2 days (otherwise I would still have to call back some time the next day).
Another example of when personal circumstance might dictate walking is if you plan to be on vacation in, say Hawaii, when the 11 month booking window opens. Since at some times of the year, that would mean MS opens at 3 am Hawaii time (the rest of year it is 4 am), I might be tempted to walk my reservation by booking before I leave for the trip. Then, while on vaation, you can call at a resonable time and chage to the days you want.
But neither of these circumstance will add much to the volume of walking, which I think in any event will be small and virtually invisible. -- Suzanne