In terms of musical groups having their own comics/graphic novels, gonna say Magic Sword's got better stuff going for them. You could argue it's also gimmicky since the members heavily keep to their mysterious fantasy sage personas and the comics are that taken to the next level, but it was part of them from the very beginning so fans knew what they signed up for. http://www.magicswordmusic.com/volume-1-dl http://www.magicswordmusic.com/comic-book
As for Green Day, perhaps they're selling this as a late attempt to cash in on their 'rebel' image. Caruso's also illustrated a book for Bruce Springsteen called Outlaw Pete and is co-authoring this one as well as illustrating. Maybe he'll use his experience with Outlaw Pete to reign in any crazy from the band.