Both the Esoterica style bags and any other bags; in short, anything other than a jar with a screw down lid with a sealing rubber gasket, will not truly protect cellared tobacco. Just because it stays moist doesn't mean that it doesn't deteriorate. Before Pease sold 8 oz tins he sold 8 oz bags, which were multi-layered, to protect his tobacco from gamma rays?-I don't know what, but particles that would penetrate other barriers. He stood by these bags, but no one else has made any such claims. Bags are not for storage but instead for getting the tobacco to you in the same state as was when it was put in them. Even short-term, bags are not recommended but they are useful as the tobacco won't be in them long enough to deteriorate.
If I'm in the mood to enjoy a tin's artwork, I sometimes keep the tobacco in it for a few days, but put it in a jelly jar very soon thereafter; I empty most tins at opening.
Even so, 16 oz tins are rare; most blenders ignore correct storage for their bulk. Think of the Gawiths bulk that sits in paper boxes, albeit with cellophane, for months. As I understand it, distributors only order from the manufacturer yearly. So if you get a box that was from the back of the pile/shelf, the tobacco can be as old as a year.