These old wrappers and proofs of old wrappers - many from 1744 - were elaborately printed by the English Tax Revenue department. The proofs were made to check the plates, and these are usually printed on thick high quality paper. By contrast, wrappers issued with the cards were made of very thin fragile paper and would easily get damaged. As they were commonplace as well as fragile they would have been disposed of once the pack had been removed. Few survive.
For some makers, a wrapper or proof is the only remaining physical evidence of their business that we have.
See also Proof Aces