A long box holds two hundred comics. Perhaps five of them matter financially — a first appearance, a low-print variant, a key issue that a recent adaptation has pulled into demand — and the rest are inventory you will move in bundles. The difficulty is that the five look exactly like the rest until you check the issue number, the printing and the cover variant.
Instica holds issue, variant, printing and grade as structured fields, so the concentration becomes visible in your own records instead of living in your memory. That also makes the grading question answerable: you can see what a book cost you before deciding whether the submission fee is worth spending on it.