Pikey is absolutely correct in stating that the contents degrade quickly for the reasons given.
About fifteen years ago I was gifted tap-boxes of Samuel Gawith snuffs for Christmas. The London Brown and Black Rappee were most affected containing dried out shotgun pellets. Had I been a novice I might not have been any the wiser.
As tobacco journalists Sonia Roberts and Jacques Cole have pointed out, the tap tins or boxes were of particular appeal to the American market and also of young people in general. But unlike oil-based German snuffs water-based snuffs degrade in tap-boxes or tins much more quickly than standard tins or drums. The cheapest and best way to secure quality English snuff is to purchase drums.
However, if tap-tins sell well and you have not received any complaints then from a business point of view there is no reason to withdraw them if the demand is there. It’s just worth pointing out (especially to our overseas pals) that they might not be receiving snuff in good condition.
High-dried snuff or even SP types might be OK for a while in one of these tap-tins but the higher the moisture level the higher the degradation. Buying moist coarse snuffs in a tap-tin is most unadvisable.