Drongo, these are apps I need about once a month or so. I used to just borrow a Windows machine when I needed them. Now I can just run them on my Mac. They are small apps that I don't use often but do occasionally need.

As for why not use Windows, becaues it is a far inferior OS to OS X or Linux. OS X is the best OS I've ever used. It lets me get my work done quicker and more easily. Can't really ask for more than that :)