Because the only shortcut symbol I could ever remember is the command key, which is also called "Pretzel" key.
I was frustrated by not being able to press a button and see all the shortcuts of my currently using app. The closest I found and loved was CheatSheet, but since I still have some minor complaints about it (such as not being able to see all the shortcuts of Adobe apps) so decided to make my own.
One thing I have in mind is to be able to execute the command on click. Feel free to email/twitter DM me if you have any suggestion.