Its not precise because it usually is using AI pathfinding to make the dude(s) move from where they were to where you clicked. It often either sucks at getting around things, sucks at getting there fast, or sucks at being exactly where you want because everything about the movement is “fuzzy” and imprecise by design.
However a point and click system such as Ultima Online where you’re simply driving the character using the mouse while one of the buttons is clicked works pretty good. Actually more precise than WASD since you can move more than 8 directions.