I use it every day. The #1 reason is because it never loses unsaved files (though I'm still working on breaking the habit of typing a few characters and pressing Ctrl-S). Column editing! Macros! Record/Playback! Configuration! Plugins! Responsiveness! Low resource utilization! Etc!
Why wouldn't I pay for it? I've bought all four versions. The author deserves to be paid.
I guess the question is: why don't you want to pay for it? Assuming here that you're a professional coder being paid a reasonable, US-equivalent salary. I understand not everyone fits that situation; plenty of us pirated software as starving college students / interns, folks in other countries don't get the same pay for the same work, etc.
We should all want to pay the authors of great software. We're on HN, which is a celebration of creating great code and awesome businesses.
"Pay him. Pay that man his money" - Teddy KGB