That's right. With *any* aiming system, you have to be exact, but that also enters the realm of diminishing returns. How exact can you get, before the player's own fundamentals (read: lack of) get in the way? Rationale: the bigger the table is, the more important cue delivery (i.e. execution) becomes. In fact, the ratio between aiming|execution favors the latter more and more as the table gets bigger. One can demonstrate CTE on a barbox all day long (and the "demonstration videos" look compelling to the uneducated eye), but take that aiming system to a 9-footer, or even a snooker table, and watch how that ratio swings in the other direction.
Aiming systems are good, but they, by far, are NOT a panacea. Once you find that spot on the object ball to hit, you now have to hit that target. This is why execution in snooker is so important, any why only in pool will you find such voluminous discussion on "aiming systems."
-Sean