Board Thread:Questions and Answers/@comment-24685938-20160430172815/@comment-34326521-20160430173417

Omnipotent means capable of doing anything. It does not mean "without weaknesses". One does not follow from the other. A being can have no weaknesses and not be omnipotent, and, likewise, a being can be omnipotent and still have weaknesses. They could be psychological or physical, but omnipotent does not mean "lacking in weaknesses".

As for why a character did/didn't do any number of actions, you'd have to ask the writers why they decided it that way.