I think it's a good idea to challenge yourself and occasionally force yourself to create; whether it be music, art, literature etc. However, if you do this expecting to have a work of art at the end, you're likely in for a shock. My guess is that it could bare fruitful ideas that are worth exploring in a more disciplined way, with no contest involved. I'd say "do it" but do it for novelty's sake and not as a new method or work process.
I agree with you, especially on this point in particular: Anyone who thinks they can give the first draft of a novel that they wrote in the span of a month to an editor and think that things will go A-Ok are either clones of Ernest Hemmingway or highly delusional. This is in no way a slight to anyone who finishes a first draft - that is a great accomplishment and one that should be praised. But writing is a process that requires writing, writing, and rewriting. And that's before you even give it to an editor. Overall, I believe NaNoWriMo is a great kickstart for a novel, but it is a novel that is a mould of lumpy clay. It needs time to be refined and reshaped and placed in the kiln before it can be taken any further.agents are not happy at all about the alleged influx of bad novels they receive through December.