Thanks for asking, I actually have practiced vim on shortcutfoo.

It is really good for remembering shortcuts for regular desktop applications, but I felt that it wasn't really meant for learning a code editor like vim.

It did not have an interactive code editor, with the ability to edit lines of code inside of it. In addition, it does not measure progress in terms of speed and # of keystrokes, so you aren't able to see how you could improve. If I recall correctly, it is just meant for remembering the command keystrokes and typing them out (kind of like using flashcards).

Also, as of right now, shortcutfoo is $8 monthly, but it allows access to all shortcut courses.

Please correct me if I'm wrong, I used shortcutfoo a few years ago.