This is a very interesting idea. It seems like doing it the way you describe, it's almost like brainstorming on steroids - forces you to go right to your worst fears!!

I really like doing visual art and writing for that reason - it's easier for me to "let myself be terrible" with them, whereas with music (my main "passion" or whatever) my ego gets all weird about it sometimes. If I was going to force myself to write a bad song, I would feel like.. IDK, like I would feel like "nobody can ever hear this, or they will think I am bad at music!! OH NO!!" With writing or visual art, it's more like "haha ok let's try this"

I'll try to make myself do this next time I brainstorm... very interesting concept.