Trying to separate you from your last dollar is not an ambition exclusive to government, and ToddG bench strips one of the private-enterprise schemes
The gist is that a $700+ handgun (the Sig Classic) ought to work fine right out of the shipping carton, without need for a $200 "action enhancement package" by the same company that sold it to you in the first place. But you should read the whole thing.
The comments include a bit about a personal tic, ramp polishing. I routinely do it to virtually every semi I acquire. Sometimes it's unnecessary, but sometimes it improves feed reliability. It isn't something you need to pay a gunsmith for if you're adept enough to strip the pistol and self-disciplined enough to live by the Two Great Rules.
(1) Remove metal by the depth of only one atom and (2) changing any angle by more than one-fiftieth of one degree is an official screwup.
The goal is to smooth the cartridge/weapon bearing surfaces, not to second-guess the engineer who designed it. We're not fixing a design flaw. We're rectifying manufacturing processes dictated by company accountants.
I use an appropriately sized dowel and crocus cloth or a felt wheel chucked in a Dremel and loaded with jewler's rouge. (Dremel grinding wheels and coarse abrasives should be locked away until the job is done.)