Despite being a skilled scholar, rocking debates with his buds, and having some serious chops in the medicine world, Faustus really wants to be known as a cunning magician. Yep, a magician. Hey, who are we to judge his dream? And lo and behold, when he gets that mojo working, he becomes powerful, rich, and famous right quick. Yet the ability of simple peasants like Robin and Dick to read and practice from Faustus's magic books suggests that Faustus's skills might not be as rare and special as he likes to think. After his death, Faustus is remembered by the Scholars not for his magical powers and clever tricks, but for the very scholarly learning he rejected as unworthy of him at the beginning of Doctor Faustus.
The Holy Roman Emperor's praise of Faustus's rescue of Bruno as a more important deed than any magic he might do is a reminder of how misplaced Faustus's priorities have become. Cleverness and cunning are fine, as long as they're in the service of good.
Faustus isn't all that clever after all. If Robin and Dick can conjure, well, then anyone can.