Why Engine Openings

Why do we have chess engines (for example Stockfish vs Alpha) use openings that humans use?
I understand we could learn how they handle those openings, but could we not also learn if the engines were to come up with new and/or better chess openings?

And yes, while I've been playing a while, I'm probably really very unskilled compared to the rest of you.
I appreciate your insight.

Engines are not very good at playing the early stage of the opening. Have two engines play against each other without an opening book and they'll come up with a second-rate opening where the position will be equal after a handful of moves, or worse, one of them will mess up and quickly get crushed by the other one, as it happens now and again. The thing is, the opening requires deep understanding of your early decisions will impact the game to the very end, which is simply too much for a classical engine to comprehend.
That's not to say we don't use engines for openings at all. There are many theoretical lines today which are the result of engine analysis.