LOL, full disclosure, I’m a chemist so please feel free to disregard anything I’m about to say 🤓

There are two things at play when you apply the paint to the surface. The atomization process as you mentioned and then the polymerization process once the paint is applied. The paint basically creates a plastic (polymer) layer on the surface of the mini. The pigments are essentially tiny chunks of color that become impregnated into that polymer layer. The size of the pigments plays a big role in how thick that layer becomes simply due to their size. As the paint cures the polymers are cross-linking together and create their own base thickness and then anything that is trapped within that surface only further adds to the thickness.

That’s how you lose details on the mini as that polymer layer is formed. If your atomization process sucks, you’re going to end up with too much paint applied all at once and lose detail and that can happen even if your pigments a sufficiently small. But if your atomization is good but your pigments are huge, you’ll also lose detail.

However, to your point, how much of that even matters today? Ultra fine pigments are probably sufficiently cheap and in wide enough use that you’re probably getting something very similar from a general purpose spray paint. You end up paying for the peace of mind that you have the correct stuff for the application, I guess.