It would be very useful to be able to place container in storage preserving the content (and to be able to retrieve it back in the same shape). Right now it's impossible.
Another idea is to protect your inventory from accidental mistaken transaction with NPCs. For example if you have a bunch of items in your inventory, and some of them are in a sack, when you trade, all items are shown, and you can by mistake sell a rare or unique item (like clicking extra time and etc.). The bad part is - transaction isn't even reversible, because after you sell the item it's gone from the NPCs items list, and you can't buy it back (may be NPCs should retain these items for some time by the way?). In order to prevent it, you can make that items which are inside containers in your inventory can't be easily sold, unless you take them out, or for example at least open that container first. This way you can place valuable items in separate containers and protect them from accidental erroneous sale transaction.
