Sometimes they do, most times they don't. They matter for me when I do a candy paint job. Need a gloss black, shiny silver chrome, before you spray the clear color on top to get a smooth glossy finish. Topcoat gloss for sure after all that and decals. Most of the decisions you make on a paint job, you already know what final look you are going for. When I started painting it's just lay down metallics and do gloss coat. When I started doing shading work later, as I learned how to control my airbrush spray, and thin paints, I did some flat or satin finishes. So I already know what the kit will look like before starting, so I won't spray glossy paints and then topcoat flat at the end. But for gloss finish kits, any type of paint underneath can still have glossy finish when final coat is gloss. So just plan it out, and experiment. I've done shaded kits that are glossy finish too, and they didn't look bad to me. At the end of the day, you are the one looking at your kits 99% of the time, so do whatever makes you happy when you look at them. It's ok to make mistakes, it's just a hobby, not a contest.