Resin is condensed smoke and vaped THC. The solids precipitate as the smoke and gases cool down in the pipe; it seems like the resin would have it's share of the "goodies".
When Opium dampers were scraped, the ash was saved and sold cheap to the lower classes. The morphine condenses out and is found in high percentages in the scrapings. For that reason they were more addictive and less pleasant that pure O, and was resold by the dens to the coolies for much less than the good stuff.
Anyway, maybe MJ resin is similar- potent, but not balanced because of the preponderance of whatever condenses out the most on the way through.