You don't have to. It was to show how to use custom arguments. You can load a different config for different games if you'd like, but for your first example it should probably be:
open -a /Location/Of/dosbox -c "imgmount a '/Users/io/Downloads/Prince.img' -t floppy" -c "a:" -c "dir /p"
No reddit for me. I stopped using it after the exodus