Good point.
I suppose the point about advertising is that it won't
compellingly instill a desire if you're not that receptive
to it in the first place. A bit like the hypnotist not being
able to make you do something you don't wan't to do.
With the affirmations you are doing them out of desire, so it
makes sense to strengthen them however you can and this in turn
increases your overall motivation.
Let us know how you get on with the programme. It sounds interesting.