Anybody see these things? Brilliant Marketing!

MILITARY GRADE!

A good clean metal paint can will work, you have to ground the can on a isolated ground rod.
Or if you need space a 55 gallon drum with the removable top with the locking ring, the top and drum have to be grounded to an isolated ground rod.
And a compressed metal seal between the bare metal lip and top, ie braided grounding cable, the flat tin plated copper cable used on old cars ground to the battery.

The grounding is what makes it work.
So the bag really would suck as a faraday cage

While I wouldn't trust the bag for anything past a mild solar storm, grounding is not helpful for EMP protection. It seems to be common to think that this happens like lightning, but it's a forced saturation event.
If a rifle shot is a lightning strike, EMP is being flanked in a coomb by Claymores. You can argue a ceramic front plate is going to work in both situations, but it's not. The grounding rod acts like an antenna, possibly drawing more ambient high energy closer in toward whatever you are trying to protect.

At that price you could afford fifty of these babies and still have better protection.

That said, Goal Zero clearly understands that their customer base is people with too much money and too little information and they are serving them to the best of their abilities.