Guild expedition is my favorite part of the game even more than bothering my neighbors.Many games have temporary items that only remain in your inventory for a certain period of time. Sometimes it works very well as it doesn't clutter up your inventory and you know up front that it's a limited time item. However, they can cause a lot of confusion and frustration. Some players complain, loudly, that the item should never disappear unless they get rid of it (usually these players are hoarders or collectors). Frequently complaints come from folks who ignore or don't notice the temporary tag/countdown timer and get very angry when it disappears. With Inno expressing concern with new players possibly being confused and unable to locate packs in the inventory, I don't see this happening unfortunately. I do like the idea of storing them if desired to be used later when I have more time or a bonus burning.
I hate the idea of competing against people who stored 100 attempts from earlier weeks. All attempts should be used within 48 hours or expire.
The only way to do that would be to store them in the expedition itself.
Most of the attempts I have won have been booby prizes, just like extra BP's or decorations. But sometimes, they have come in very handy indeed.