File installation paths

I have always liked to install programs on my machine in easy to manage files on my desktop. I use a lot of music editing software and install most of these in a folder called “MUSICAPPS”. All programs have their own separate folders within MUSICAPPS. It looks like this:
C/WINDOWS/Desktop/MUSICAPPS

Getting on with the question, I have a friend who persists on telling me that it’s best to install programs to the program files folder and to only use shortcuts on the desktop. The only reason why I wonder, is when you install a new program, it always wants to default to program files. I would think that if I can understand the setup, it should be fine for my computer. Maybe it makes it easier on the HD? What’s your take?