People will always disagree on the value of CRM - I think a lot of hype is generated by buzzwords.
I think in it's most basic form CRM can should be considered as knowledge rather than as a practice - ie you do not have to actively sprout CRM to be an effective crew member.
It is common knowledge that something like 80% of all accidents are caused by human factors. To my mind the object of CRM is to study what went wrong in these accidents - learn from other peoples mistakes as it were. If you think about it where else in your training is any of this covered.
This brings me to the point that CRM is knowing what your limitations, as well as those of the rest of the crew are.
At the risk of hijacking the thread - I would be interested to hear what a good CRM course should cover.