Returning to the OP:

What do people think of the term?

Pretentious, vague and hype-tastic.

What do people think of the idiom?

Well, I liked the Weed Tree. Generally what it brings to mind is a lot of wifty-wafty "ooh, how magically inspired we are" mood-pumping, at least at one end of the spectrum. Exactly like what Bright Phoebus wasn't. The darker end I haven't frequented much, because just reading about it scares the crap out of me - probably more than actually listening to it would do, although I don't feel inclined to take the chance. (Probably a fair amount of mood-pumping going on down there, too.)