The third combination of the three great characteristics is omnibenevolence and omnipotence. This is a character who loves everybody and everything, has the power to make everybody happy and joyous, but has no idea how to do it. I think this is also a fairly tragic character. Much like the omniscient and omnibenevolent person, they want to help and do good, but are unable to do so.
We often see a character like this when an average person is magically granted super powers. They want to do so much, and now finally can, but every time they try to help somebody, they make a situation worse. The lesson is usually that it's better to be a mortal with limited powers if you can't handle them - either that or not everybody can be helped. They're both pretty shitty lessons if you ask me.
What I find interesting is that this character could respond to the situation in noticeably different situations. Somebody who tries to help and fails consistently could become gun-shy. With enough failures (or causing a significant catastrophe), one might decide to hide away forever. Without that fear, a confident person could continue to try, time and time again, dedicated to get it right.
I guess the main difference is how you determine omnibenevolence. Is it better to risk harm to others in hopes of helping all, or is it better to not take the risk to make sure you cause no direct harm?
I don't know. And since these people aren't omniscient, neither do they.