[lorenzhs]

There's a lot more in the German version of the article, including a second possibility of what they were used for. A number of reasons is listed why it might make sense to consider them places of refuge in case of an attack:

- entrances are generally hidden

- narrow slip holes make defense simple

- locking mechanisms that can only be operated from the inside were found

- some are directly connected to fortifications

But it would also be excessively easy for an attacker to just kill the inhabitants by sealing the entry / smoking them out if they were found. They're also rather unsuitable for prolonged hiding (little space = little air, need to bring food, no way of getting rid of faeces other than burying them), but 48h have been experimentally confirmed as possible for 3 adults.

[ohitsdom]

It'd be jarring enough to climb through such a small tunnel. But to hide there, while someone who wants to kill you waits outside? I'd go crazy.

[DasIch]

I'd assume that you would only hide in such a tunnel temporarily and not in sight of an attacker. Just stay in there until it's night, the situation calms down and it's easier to slip away completely.

[lorenzhs]

Yeah, I'd assume the point would have been not to be found in the first place (otherwise, why hide the entrance?) and to be able to defend against attackers if they do find you but didn't think of just letting you suffocate in there or smoke you out. In that case, you'd probably have a better chance of survival in an Erdstall than pretty much anywhere else, right? The scenario might be a bit contrived though (wouldn't attackers pick up on the "just let them suffocate" tactic rather quickly?), but then again if the explanation were on hand then there wouldn't be a mystery to debate :)