That's it in a succicnt nutshell.
If you are a long-time prepper, and have all bases completely covered for a lifetime, there are maybe 3 things you could do with a pile of surplus fiat dollars:
1) Leave them in the bank, and watch it lose 10% of its purchasing power (again) over the next 6 months.
2) Invest it and only lose 8%... and tie up all options for a year as well.
3) Buy preps you now don't need, and will never be able to use unless you live to be 200. Meaning not just buy MORE, but buy several hundred thousand$ more.
4) Buy gold and silver.