Never had the desire to eat them, myself. I do know they have become quite intrusive in many of our Vilas county lakes. You aint a kidding about the lack of weedbeds - the cabbage is virtualy nonexistant in many of these ecosystems. IIRC, the DNR has done two things to fight this rustic crayfish problem - (1) they have contracted to have them trapped & removed, (2) they have introduced a hybrid crayfish which can not reproduce, so as to intermingle and hopefully help extinguish the population.
Star & Plum lakes come to mind.
And yeah, the smallies, and their preservation should indeed help combat these dang crawfish. Encourage all to release the smallmouths when fishing there lakes/rivers.