Yes!!
I was gifted one on my birthday, a 2 key macro keyboard. Your one looks really cool, with the dial and all.
Using one of these has been greatly useful for C3 and Paint.NET (e.g. when doing repetitive tasks).
I also recommend checking out AutoHotkey if you aren't aware of this. It's a bit confusing at first but it's worth learning about. I setup a macro to auto-type a date stamp, so when I write a comment in C3, I can tap on the key and instantly leave a date stamp so that I know when I wrote the comment.
Too bad I knocked it off my desk by mistake and one of the keys stopped working...