People use what works for them. For prototyping it works fine. Not my cup of tea. I'm not a systems programmer, I only write tools in Python, Bash, and still awk. Since I work in a primarily *nix-based environment, I use mainly Kate as a poor-man's IDE and the shell, usually Bash.

I've got friends telling me I should switch over to VS now that it runs on Linux, but I'm too stuck in my ways to change, and I like my workflow minimalist as possible. Most of the time, I rapidly prototype something on a development server and then once I know the idea is feasible, I'll move over to Kate and write it more cleanly, since Kate has Konsole built in. I can make changes and run them immediately.