Good at everything that doesn't count?

Gibbon writes (Chap X) "It is difficult to paint the light, the various, the inconstant character of Gallienus, which he displayed without constraint as soon as he became sole possessor of the empire. In every art that he attempted his lively genius enabled him to succeed; and, as his genius was destitute of judgement, he attempted every art, except the important ones of war and government."