As others have mentioned, the round can is most likely a product from a local or regional retailer that purchased bulk powders from Hercules (and others), then re-packaged for retail sales. Very common practice prior to about 1980.
When I started reloading in 1972 bulk powders were very commonly seen in sporting goods stores, including US military surplus. Most came in sealed barrels (various sizes) as used to fill contract sales to ammunition manufacturers and military ordinance plants. The store personnel would either re-package into retail-sized containers (paint cans were commonly used) or simply scoop from the barrel onto a scale, then dispense in a brown paper bag.
I used emptied powder canisters repeatedly, simply applying adhesive labels to identify the contents and date of purchase.
Purchased a lot of bulk surplus bullets and primers also. Bullets were weighed to establish a quantity based upon individual bullet weight. Primers were in cardboard sleeves and cartons, packed in wooden shipping crates, so easily sold by the thousand.
I recall IMR rifle powders for as little as $2 per pound, surplus bullets for about $15 per thousand, and primers were about $3 per thousand, back in those days.
Personally, I never intentionally kept powders for more than a couple of years, but I have occasionally used powders much older (properly stored in sealed containers) without issues. After my last change in houses I found a stash I knew to be nearly 20 years old, kept in a dry dark basement at moderate home temperatures.
Older samples like the OP's are probably of more interest for collectors or display purposes, although there may be some individual users ready to buy due to the recent years of shortage.