Sure. (more than you asked, but I may forget and need to come back are read this later)
Picture, if you will, a gun safe with many SIGs, all with unpolished ramps. We will examine one closely and find many machine marks across the ramp. Under magnification, we would see parallel ridges and valleys, much like a dull file.
As the projectile is stripped, ideally the magazine feed lips will help lift the front of the cartridge. Then the bullet shape, ogive and meplat, will facilitate a smooth transition up the feed ramp and into the chamber as the cartridge base is forced to slide up the breech face and under the extractor claw as the slide goes fully into battery.
BUT, the common metals used in bullets, lead, zinc, tin, copper, are all very soft and malleable compared to the steel feed ramp. At first impact with a rough feed ramp, the ridges of the ramp peen into the metal, causing the soft metal to flow into the microscopic (well, bigger than that) valleys of the ramp - all this on a tiny scale.
Lets do a stop frame here. We have a projectile who's meplat or ogive have just hit a rough surface which has stamped itself into the bullet metal, drastically increasing friction and starting to rapidly decelerate the slide. One of two things will now happen. The projectile will have some tiny amount of metal removed* as it is forced to slide across the rough feed ramp surface. Make no mistake, the forces are tremendous as they are focused on only small area of the projectile. Nevertheless, the round chambers and our blissful shooter may not even be aware of how close to a feed failure he has come. If it were colder, the gun was dirtier, less lubed, who knows? But one thing for sure, reliability is lessened by that rough feed ramp.
*No doubt you seen a feed ramp with copper or lead streaks on it? That's why.
In the second scenario, the friction between the bullet and ramp is simply too great to be overcome by the inertia of the moving slide and the power of the recoil spring. A fail to feed occurs.
Polishing a feed ramp isn't 100% necessary. Many guns function fine without such doting care. Too, other guns function fine when torture tested or run without cleaning to see how many thousands of rounds can be fired to point of failure. None of those guns belong to me. On that gun run dirty to failure, how reliable was it a few rounds prior to failing? An extreme? Sure. I want my gun's extreme to be in the reliable direction.
Polishing a feed ramp may be gilding the lily, but it's never a waste of time, even on a gun that runs fine with a factory finished ramp that gets "color" from bullets. What is does for that already reliable gun, is increase the "reliability margin" by some amount. You won't quantify it, but it's there. I want my gun to be as far from that ragged edge of failure as it can be. My feed ramps sparkle like a diamond in a goat's behind.