I get it. It ain't rocket science.
Just maybe we can recognize that writing is an important capability in the
progress of human history. (apparently email is the exception ;-) Writing is
good. Writing music is good. Writing solos is good. Other ways of retaining
information may also be good, e.g. memorizing. When trying to memorize,
multi-dimensional stimuli are more effective. Thus, to memorize a musical
passage, learning to sing it is a helpful step. Note this does not mean it is
a necessary step, nor the first step. Writing it is also a helpful step,
probably more exact and more persistent. It is certainly easier to share with
others (without having to go out and buy somebody's CD).
In my humble opinion, learning to sing a passage enhances one's appreciation
of it and deepens one's emotion for it. To raise this simple, elementary
experience to an exalted method by which we should all learn jazz, and
without which we cannot be true believers is nonsense. To think we should all
follow it as the one true path because a famous musician did this and
advocated it (perhaps because it fit his own special needs very well) might
be just misguided hero worship.
Then again it might be salesmanship, as in marketing one's product (note the
"contact me for further truth" echos embedded in those messages).
Hopefully we can get on with other things now.
PS: Please don't turn it into a sophmoric debate on the wonderful,
transcendental purity attainable by internalizing through memory vs. the
crass rationalism of written notes, insufficient as they are to render all
aspects of a performance.
Hey man, even Dennis Hopper has moved on past the sixties. Get over it.