Here are the other reasons:
1. Part of my Life Goal
Becoming an author is part of my life goal.
The authors I admire are Mark Twain (Samuel Langhorne Clemens), Oscar Wilde, George Bernard Shaw and Arthur Conan Doyle. I love their style of writing. But they all started as struggling artists. Bernard Shaw's first 5 novels were rejected. Mark Twain didn't make any significant money from his writings till he was about 38. It was the article he least expected to intrigue people that made him a national sensation. Oscar Wilde is the clearest thinker I've encountered. Doctor Arthur Conan Doyle spent more hours writing short stories than working on patients. His private practice failed because of that and even though he wasn't making any money from his writings, he kept on writing. In the end, his short stories on Sherlock Holmes made him a national hero. People begged him to continue when he stopped the series.
The one thing they all have in common, and that I'm trying to acquire, is writing almost daily. I don't want to be popular or make a killing from my writings; I only want become a prolific writer.
2. To improve my grammar
Just for the few months I have been writing daily, I have noticed considerable improvement in my grammar. And I know that if I keep writing daily, in a few years, my grammar will be almost perfect and I would have become a compelling writer.
3. It gives me inner peace
Because I write about everything that interests me, I'm able to free my mind. It helps me be at peace with myself. I've got a powerful avenue to express myself and daily too. I don't have anything bottled up in me. I sleep lighthearted every night. I wake up with ideas. And I have a sort of an inner peace.
4. It helps me examine my life frequently
Knowing that I'll have to write about every life decision I make helps me be more deliberate in my choices. I not just do things because everyone is doing them; I have to think about what I'll have to say on my blog to justify my decisions since one day I won't be able to (further) resist the temptation of writing about them. Also, writing everyday forces me to evaluate my life every couple of days for interesting things to write about.
5. It gives me the feeling of "Nothing is Impossible"
When I took the decision to begin writing daily, a part of me believed I would burn out in days. In fact, I was expecting days I wouldn't be able to meet the goal. But now, about 3 months after, I'm almost 100% sure that I can keep doing this. And it has encouraged me to go after other goals in my life. I now strongly believe that popular quote, "You never know what you can do till you try."
And those are the reasons I write at least an article a day.