Why I like typing
If I'm having a conversation with someone on IRC or an instant messaging program, I can consider my words. I can edit the earlier part of my sentence if I decide to word the end of it differently than when I began. If necessary, I can write an entire paragraph so the sentences come as a whole piece, and can't be interrupted by tangential questions or comments in the middle. I can multitask while waiting for a response, without truly missing anything.
There's also some truth in just that I am better at typing than many other people. I'm not special as a talker, but as a typist I can get a thought out quicker than most people. Plus by actually using capital letters, punctuation, and full words... I come across as literate.