NaNoWriMo Day 5

Day 5 of NaNoWriMo and I'm really enjoying myself. My story is going well so far, with what I am considering a very "Joss Whedon"-esque opening sequence (though others might disagree that it is). I think I may have hit on an idea for a possible series, expanded from this story. Matti and Eva are currently 17 and 14 respectively, but I have ideas for what they would both be like as adults and the story is expanding so that there is scope to follow these girls out of adolescence and into adulthood and see how their powers develop.
I've spoken to a few people who don't believe that NaNoWriMo is a good thing, that it only produces dross, that it's not productive, etc. Mostly I think they believe this because they've never been able to do it (ouch), but I'll summarise very quickly (I have a novel to write, you know):

Why NaNoWriMo Is Good
By Lucy Wade, aged 30 in exactly 20 days.

1. NaNoWriMo gives you a legitimate excuse to fob off friends and relatives and actually do some writing.
2. Even if you don't hit your daily word target, the fact that you are writing daily means you are probably going to be more productive than if you weren't doing NaNoWriMo in the first place.
3. It is an ideal way to write a first draft of an idea you want to develop - like one 50,000 word treatment. You can play around with tone, plot, structure, narrative devises, until your heart is content.
4. You can tell very quickly if the idea you've been toying with has enough steam to become a novel. If you're finding it difficult to write even 10,000 words, then it might not be developed enough at this stage...
5. But that's also a good thing, because not only have you saved yourself potentially 10 years figuring out that your idea is lousy, you now have a month to fix it! Or evolve it into something completely random and new. Never will your imagination be so free!
6. Developing the discipline to write 1,667 words a day (or possibly more) is a major achievement in itself. Turn off that TV. Don’t stop for yet another tea break. Just do it!
7. You get an immense feeling of satisfaction when you finish. You know afterwards that you are capable of writing something novel/novella sized - yes, it may be riddled with typos, and characters that change name, or eye-colour, or gender half-way through, as well as plot holes the size of the Grand Canyon, but isn't that normal for first drafts?
8. There's an excellent sense of community, one that doesn't normally exist for writer's at other times of the year. Over the course of November, you have 172,000 other writers sharing your journey and cheering you on, helping you out of tricky spots with suggestions on the forum, or providing you with procrastination when you think you can't type any more.
9. You have to write 50,000 words by midnight 30th November, but there is no adjudicator as to "what" those words are. You could simply write "NaNoWriMo is great" over and over again until you hit your target, but you don't, because it would only be cheating yourself. Giving yourself permission to try and seeing what your imagination has in store for you is one of the best, one of the most liberating experiences.
10. It is free, and you get a certificate at the end.

OK. Kinda trickled off at the end there. Anyway. Time to write another 1,000 words of my novel. Happy Diwali and Bonfire Night!