I was just thinking about this sort of thing the other day. Thinking if I need a techno 'bug out' bag, my Macs would be the most useless ones to waste the weight on because if anything happened I'd never be able to reinstall macOS without phoning home to Apple for an activation.
Trouble is a Linux-on-a-key that you've never used before, is still a long way from being productive without a network to install all the packages you actually want to use.
It takes me about a month after a reinstall or new machine, to feel like I've really spread my wings and have everything installed that I initially forgot about. So I guess the recommendation would be "daily-drive it for a month before refrigerating it". And at that point, you might as well just make it your everyday machine.
It's time to sell your soul to Big Penguin.