Chess is not a game where there is always one right move, but where positions are threatened/protected to a greater/lesser degree, and the _value_ of those threats/protection can only be realized much further along in the game.
The best players in the world, these 2700+ rated players have:
1. Played many many positions many times over and have incredible recall of those general positions.
2. Know how to analyze a position/state of the game at any given moment and have a better "feel" for who is advantaged and/or where the greatest strengths/weaknesses of black/white are located.
However, none of them have the power of chess engines, which analyze singular moves (or poll a db) for the hundreds/thousands of possible outcomes 1, 2, 3, ..., n moves ahead (this is why the best engines are strictly better than humans at this point), so unless a player has both played and committed to memory the exact line being played in a game, the best they tend to get to is "having a feeling" about the state of the game (please forgive my oversimplification here, chess fans)
Now if a 2600 rated player - someone who's still easily in the top 1% of chess players and incredibly capable player of the game - were to be playing a game against a 2800 rated opponent, but had a computer tell them "Hey, this one move is critical" without being told the exact move, they would almost _certainly_ become heavily favored to win. That "feeling" about a position is now irrelevant. There are only a few pieces that will be likely moved on any given turn, and now you can narrow down your own analysis to what is different about moving any one of them in particular because you've been given advanced warning that the most-likely-to-be-played moves will result in wildly different consequences n moves later.
These are hours-long games. Taking 15-20 minutes on a turn is not unheard of, and doing so on a turn that is proven-critical can make all the difference.