I like the concept of constraints to boost creativity. When you are forced to do less you actually have to work harder. Sounds contradictory right? But think back to high school or university: the number one thing my professor would always say is "write less and be more succinct".
In most cases writing five pages is actually easier than one. That's because you have to distill multiple concepts, ideas, arguments and resolutions into one neat little body of work.
The same principle is applied here at 200 WAD. Lately I've been trying to stick to a 200 - 250 word limit and no more. This has been a really fun exercise, because once I've written my daily post I go back in and think about how I can cut the fat.
Sometimes it's just a word here or there, other times it's an entire paragraph. It's actually a really satisfying practice. You start to think about your prose and look for wasted words that add no extra value to the sentence.
When writing 200 words, I like to think of the reader. No one wants to read a novel when they came for a short story! As a reader, I'm expecting 200 words, not 800.