Cryptocurrencies have an element of risk, heck the technology is only a few years old, and they do depend upon the Internet, but it's not only cryptocurrencies that have the Internet as their Achilles heal nowadays, it's banking, resupply, transportation, travel, security, manufacturing, and many more critical systems that we rely upon today. I would never advocate sinking more than what you could afford to lose in any one thing.
And talk about fiat money, good grief, what exactly determines the value of cryptocurrency? Mining, lol? I remember my young niece being fascinated with Minecraft, not exactly a big money-maker for her.
There are plenty of informative videos on Youtube that explain the process in detail, for those interested. I can tell you from 3 years of experience that "mining" ain't so easy. It requires equipment, time, and lots of electricity.
Dont put your faith in any form of currency if you believe the governing systems to which they inevitably belong will cease to exist. Scrip and local currencies will arise in the absence of any other alternative, as they have in the past, with the value agreed upon by those participating and policed by those participating as well.
True, diversify to an extent that's practical for you. One of the best forms of currency ever invented, utility wise and at this day and time, are Cryptocurrenices, IMO.
If you’re planning for SHTF, it’s best not to pin your “money” to the fan, though.