All of my childhood friends who bragged about being good at GH/RB only ever bragged about being good at the _games_. Never ran in to someone trying to pass it off as being able to play the guitar.
Anecdata, friend. Two old friends became extraordinarily good at guitar hero and even won competitions. They're also some of the best guitar players I know. One of them is an extremely good drummer and can do improv piano like a beast. They'd both agree that guitar hero helped them play better.
What are your thoughts on games like Keyboard Hero?
Maybe not, but folks keep telling me that I'm ignorant for not agreeing that being able to "engineer" a prompt is the same exact thing as being a poet or painter.