Capablanca preferred playing quiet, positional chess, often patiently nursing tiny endgame advantages into a win. It's generally much easier to play accurately in simple endgames than complex middlegames, and that's a big factor in his low ACPL score. (I don't mean to take anything away from him - he was probably the best ever at that style of play.)

In part high accuracy means that the opponents are approximately of equal strength. The way people win games in chess is by complicating the position so much that it forces your opponent to make a mistake while you are able to handle it.

If the accuracy is high, not only it means that the players are good, it also means that they don’t ask each other serious questions. Put any human against Stockfish and, I am sure, their ACPL will increase dramatically.

Capablanca without any doubt. Also Morphy.