I think they're generally a smart option for super low usage scenarios, or visitors from out of the region.

I considered taking one, vacuum packing it and stuffing it into my Ditch Bag on my boat as an additional emergency solution.

The x-factor is how quickly the "minutes" expire (either to dis-use, or failure to re-up and buy more)... Sometimes they last only a few months, which makes them bad for emergency scenario usage. That's the x-factor to really watch.
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The charm of fishing is that it is the pursuit of what is elusive but attainable, a perpetual series of occasions for hope. -John Buchan