I have been trained (MUCH less training than CJK) that tension pneumo comes after traumatic injury and not spontaneously. And while I’m trained and equipped to treat it, if I can’t get a victim to definitive care quickly I wouldn’t be optimistic about their long-term chances.

In other words: I carry the gear because I know how and when to use it, but in a long-term situation without definitive care available, it’s of much less value.