I "mined" about a 1,000 pounds of fired bullets from a dirt berm at an outdoor range. I also was there when people were shooting, so I know that plated, powder coated, jacketed, and plain lead bullets were fired.
I assure you that neither the powder coating nor copper plating will strip off your crimped bullets. When the 'melt' gets hot enough, powder coating will burn off or become black goo that disappears. The copper plating has to be 'broken' so the lead runs out.
My conclusion is that a crimp on the bullet will not cause the plating / coating to strip off when the bullet is fired. Most cast bullets with larger lube grooves (not tumble lube bullets) still had some bullet lube in the grooves after being dug up from 4" - 6" underground.
EDIT: If you have a quart of liquid Alox, 5# of beeswax, a full bottle of Johnson's liquid floor wax, 2 cans of Johnson's paste wax, and 2 Lyman 450 sizer/lubricators, you just don't want to invest in powder coating. I can't comprehend the joys of coating bullets, standing them up just so in a a baking pan, bake ~20 minutes, cool, recoat, size, whatever -- it ain't going to happen.
I've worked out the bugs of casting, sizing, lubing, and loading lubed cast bullets. At this point in my life, I'll keep doing it my way while still using my flip phone. 
