I've played with some bar house sticks which have an almost flat tip.
These miscue a lot. Also when I draw, the ball scoops (jumps) when hitting as low as I do with my dime shaped tip. I can get draw and not scoop the ball if I hit higher up.
So It seems to me I can shoot quite low on the cue ball and get good draw with a dime shaped tip. But if shooting this low with a flat tip, it will scoop the ball.
When you are shooting the cue ball off center with draw, follow, or english, it is the edge of the tip which is contacting the cue ball. Seems to me a flat tip would not have much surface area touching the cue ball when shooting off center. Thus I would not think it would "grab" the cue ball very well - tend to "slip off" instead.
Also Predator says there is less cue ball deflection with a dime shaped tip than a nickel.