Board Thread:General Discussion/@comment-32910370-20170821013031/@comment-25430354-20170821020119

You're basically answering your own question on why Devil Hulk wasn't used:

" hasn't been shown using its abilities in the comics"

" prevent him from escaping Banner's mind"

Even the hardcore Hulk debaters don't use Devil Hulk since it's not something that he could just easily access. It's been introduced nearly a decade ago and Hulk's shown no side towards going that route. Even his evil alternate future self Maestro is no Devil Hulk. If Hulk were to go all out with his power, Worldbreaker Hulk would be the one to use since Devil Hulk's held back too far to make an impact at this point.