There are many reasons to cellar and age tobacco, and I would break them down as follows:
Why age tobacco:
* Aging significantly improves the taste of virginia and oriental tobaccos. Latakia is muted through aging, and since I am not a huge Latakia maven that is not necessarily a bad thing. I love a good aged English blend where the flavours of the virginia and oriental tobaccos are heightened through fermentation while the latakia is more muted and smooth than it was when young. The impact of aging on burley and perique is more debatable. I can't comment on burley, but I love how perique ages - oddly, it either gets more "plumby" or it gets more peppery, depending on the blend, and I like both results.
Why cellar tobacco:
1. A hedge against general upward inflationary pressure on tobacco prices.
2. A response to the concern that existing state tobacco and sales taxes will be applied to internet tobacco sales by out-of-state vendors through the introduction of internet commerce legislation.
3. A response to the concern that tobacco taxes will rise in the future, as all sin taxes have a tendency to do (some may call this paranoia, but just because you are paranoid doesn't mean someone isn't following you)
4. A response to the concern that future legislation may restrict internet tobacco sales, thereby reducing access to a wide variety of blends.
5. A response to the concern that increased FDA regulation of pipe tobacco may result in certain blends being discontinued because they are no longer economically sustainable or because they contain flavor additives.
6. A response to a more general concern that one's favourite blends may be discontinued for reasons unrelated to increased regulation.
7. For pipe aficionados outside of the US, a response to the concern that future changes in their home country legislation and/or customs enforcement will make it increasingly difficult to import pipe tobacco across the border.