John,
IMHO, I do not believe one can correctly say a cue ball struct by a tipped cue stick moving in a straight line vector would have the exact same effect on the cue ball as one struck by a tipped cue stick where the tip is arching downward through the time of contact time with the ball, even IF struct at the exact same point & all else being equal.
IMHO, When the tipped cue stick strikes the ball going straight into & maintains that vector while another tipped cue stick strikes the ball at the exact same point but is arching downward during contact, the effect on the ball can not be 'exactly the same'.
IMHO, The difference might be slight but if the tip vectors are different then the result must be different. It is in every other sport or game where hitting a ball is involved. Why would hitting a pool ball be different? In other sports different follow throughs or finishes are indicative of something different that happened before contact and different causes have different effects on the ball. Again, why should hitting a pool ball be the only ball that is different? IMHO It should not be & it is not different except in the degree of the effects due to the hardness of it's make up.
That is probably why we hit it with the linear line of the implement, the cue stick, & why we put a leather cushion on the end as well.
Some will say that any difference is 'insignificant'.
I say any difference is 'significant' to me & IMHO should be significant to any serious pool player.
Just my humble opinions.
Best Wishes & Regards to you, John,