I both store and charge my lipos in a sack.
I have 2 of those Racers Edge sacks from Impakt RC.
I don't see a reason not to use them. It's not a hassle or anything.
How else do you transport all your packs around? When I go out I usually have 6 or 8 packs.
I've never had a problem charging any of my packs. (although I have farted)
The only fires I've ever had were esc's.
I use them at the track just out of respect for others and for safety.