Do you pro's use more than one aiming method ? I mainly rely on Ghost Ball, or Parallel shift... I have to see the Contact point or Ghost ball position. Occasionally, when I look at a shot, and try to guess ball overlap, I'll undercut the shot. I have to take the time to confirm Ghost Ball/ CP...Occasionally, I try to envision a rail behind the OB on cut shots. The more info the better, correct ?
More than likely you are seeing the aim or line correctly, but your delivery is not congruent when you pull the trigger.
This is why, sometimes you apply a side spin of left or right and miss and notice no spin on the cueball. That's a miss stroke.....in general.
When you apply side spin and over cut or under cut, that is a visual alignment mistake.....in general.
Sometimes, depending on what side or part of the table, visual alignment and or stroke, will skew the equation and virtually do the opposite of what you want.
Shots you typically miss thick, it's typical to remedy this by thickening up the visual in the stand up and go into address on that line and trust it and you'll notice something very different at address, mainly, your stroke will feel more freed up.
And vice versa for over cut misses.......set up thinner in the stand up.
Side spin itself helps lubricate the contact but does not throw the object ball if you truly are aiming thick. You need skid in the form of draw or even force follow high English to achieve this effect.
Its hard to know these things in real time but the misses will tell you the story if you know what to look for.
The bottom line though for makes and misses is alignment from eyes to feet and all the way to stroke.
To achieve all that awareness is not easy and using any kind of aiming systems for particular shots is part of the remedy but so is none and just relying on pure alignment delivery down the path of the shot relationship.
Align or aim is one in the same but still different in a sense of approach and methodology, therefore different, therefore 20+ years of arguing.
Aiming has many gaps that needs filling, aligning has none but needs a ton of time to understand and solve.
Both are methods that should be understood or utilized to form a complete system depending on player objectives and goals.
The more you wants to beat, the more you gots to know.