Ancelotti benching Mbappe? It is not conservative; it is calculated. Let the young observer examine and grow. See the flow of the game, where the weaknesses are. Then let him free. There is no pressure; only instinct guides here. Ancelotti knows how to handle superstars. He will have head right of Mbappé. Particularly with a team like Real Madrid, confidence is absolutely vital. Though they demand enthusiasm as well, the fans want goals. Mbappé has to demonstrate to them his both. Tonight's the night. Las Palmas is the perfect opponent. Mbappé is hungry; he is fresh. Anticipate him using every flaw and error. Here he shows he is not only a superb athlete but also a Real Madrid legacy in development
Ancelotti is an experienced coach, so benching Mbappe must have a good reason. It's not possible for Mbappe to play in every match. There are some games where, if Ancelotti thinks Mbappe is not necessary, he doesn't need to play him. Currently, Real Madrid has many star players, and it isn't necessary to play all of them. The truth is that each of these players has their own functions, and it is only when necessary that the coach should use them. So, I agree with you that football is also based on calculation, and that’s why experienced coaches always win—they know the best time and matches for each of their players to play.
Mbappe has not yet adapted well to La Liga, and the new position does not seem to make him comfortable yet but, he will likely remain become a starter in the 3rd game against Las Palmas. It could be an opportunity he cannot afford to waste because if he fails to score or does not play impressively again and while his replacement can do what is his job in scoring goals, then most likely Ancelotti could put Mbappe on the bench in the next match.
Honestly, it always takes some players time to adapt to the pattern of play a team has. It's very possible that Mbappé has not yet adapted to the team's style of play, which is why he hasn't been scoring as much as he did at PSG. However, I believe that with time, he will adapt. Mbappé is a very sharp player, and once he regains his scoring form, it's very possible that he will start breaking some records. But all I believe is that Mbappé will surely play for Real Madrid and win many trophies. Let's see what will happen in the next match; maybe Ancelotti will bench him again.