Paintballers sometimes use them to store small amounts of ammo. My experience was that cheap plastic cigar tubes would allow moisture inside over time, which caused ammo to get lumpy & spoil. I'd expect that they'd make so-so containers for survival items.

They do have a few things going for them, though. They can be cut to a shorter length if you want. Paintball websites sometimes sell caps that stay clipped on to the tube so you won't lose the cap on the ground. Also, the tubes fit very nicely into shotgun ammo loops.

They do make nicer, aluminum cigar tubes that (I think) are airtight. They come with one of those desiccants built into the cap, but I think they expect you to soak it with water to humidify your cigars instead of keeping things dry.