I used those, and several other versions of the currency, each defined as 1000 of the previous unit.
x1000, then x1000, then x100, for the full story.
But guess what, the economy kept working in spite of that. badly, of course, but it did. Sorry if that disappoints some, but civilization did not collapse.
And people did not get utterly ruined. No sane person "invests" in cash;
(my bold)
The primary purpose of money is a store of value, so that it can proxy for products and services in commerce. It must retain value over time to properly function. If it doesn't then the whole economy is badly distorted, made inefficient.
when the inflation gets too high, banks will offer inflation-corrected savings and investment funds, that allow fast deposit and withdrawal at any time.
You know, of course, about the horrendous
corallito, and how the banks ruined thousands of savers. This has been practiced in many countries, not just Argentina and Cyprus. Also, investment (pension) funds have been raided in numerous countries, like Hungary and France, in recent years.
Inflation, like salt on food, is good in small doses, disastrous otherwise. It must be just big enough to dissuade people from hoarding the currency. Inflation of 5% per year requires adjustments in salaries and prices, each year or every 6 months, and must be explicitly taken into account in planning or contracts spanning many months. Beyond that, inflation begins to be a real pain: prices and salaries have to be adjusted all the time, people must rush to invest the salary, etc.
Hoarding is simply the same as saving. Savings are what makes capitalism a viable economic model. Inflation is a stealth tax from those who have last use of new money (the poor, middle class) to the pockets of those who have first use of new money (the banks, wealthy, government).