But you cannot apply the tabletop rules 1:1 to the PC game. In combat, a grid space of 5ft. doesn't represent the whole space that your character takes in rather than your reach. and it also counts as difficult terrain, in my opinion representing the bypass you have to take, to reach your destination - which is implemented through collision and different pathing in the pc game.
if the implementation and path generation is optimal is a different question, but it captures the spirit of what 5e rules try to say. Therefore, I would say the statement "It is in the rules" is missleading at best.
