I'd like to have options open to me. Right now, I can only do things through PHP. What if I wanted to run a Minecraft Server, or dabble with Radio2, or use lighttpd, or just generally rethink the way I publish on the web. If I could run my own mail-server, then I could move away from Google. So there's lots of possibility, but I won't really know what sticks until I try and PHP is not nearly enough.