There is no better definition of the centerline of the cue ball than the patch where it meets the cloth. Some only move from that alignment on the final stroke. I have to admit that after finding center I prefer a practice stroke or two aligned with the contact point I plan before hitting the cue ball.
There was a time when people tried to hoard knowledge including exactly where they hit the cue ball. That time is long past with the information readily available now. Then there is purity of stroke. A fairly raw player isn't going to get the same result trying to hit the cue ball in the same place as an accomplished shooter.
Satisfy yourself you know where centerline is at, offset to suit, shoot. Pool could be a simple game if we didn't spend so much time trying to complicate it.
Hu