to clarify: by first responders I meant bystanders, not Fire/LE/EMS.
I would be curious to know more. Were these individuals professional first responders/military? What sort of injuries were they treating and what was the time-to-hospital?
For your average Joe Blow living in an
urban or suburban setting,
odds are good that the time that will elapse between calling 911 and EMS arrival will be very short. The diagnosis and treatment of tension pneumothorax ( aka TPT, for which the chest seal is intended) is far less intuitive than the indication/application of other bystander interventions.
Typically (but not always), TPT takes time to develop, and by that point most patients in most settings will already be onboard the ambulance or in the ER.
In my amateur opinion, I'd rather have someone with minimal medical training focusing on other aspects of first aid (hemostasis, CPR) while they wait for first responders to arrive. In the grand scheme of things having a chest seal on your person isn't bad, but like everything else you can only be the master of so much. For a non-professional with BCLS training or less, it seems to me like a far better use of time/mental energy/pocket space to focus on interventions that are dirt simple and immediately life & limb threatening.
Here's a
good review article on TPT. Note they specifically discourage the indiscriminate use of needle decompression.