Go players, even bad ones, often play moves that simplify a position -- capture "dead" stones, remove aji -- even though they aren't the largest points value available on the board. We do what we can to reduce uncertainty in the service of maximizing win probability even in the face of being bad calculators.
Yes, but they're essentially just scraping the surface of those types of moves. In chess it's similar — I'll happily trade down "losing" material to a won endgame. But humans do these things typically only when they can get to an ending where they're 95%+ sure they will win.
AlphaGo will do this in any situation, from the beginning of the game all the way to the end.
