I (obviously) have heterodox views, but this is why I'm attracted to cryptocurrencies. But you asked, "Why would we want to give [central bank currency] up?" so I am explaining in good faith my honest opinions.

I don't think inflation is a good thing in any capacity. Inflation is a redistribution of wealth away from savers to receivers of freshly printed money. Inflation also encourages mindless consumption as currency holders know that they have to buy something, anything in order to escape the destruction of their savings. This is much more common is countries like Brazil, but the same principle applies to every country. Furthermore, I don't like that essentially a few people (central bankers) ultimately decide where new money goes. Corruption in the US is less-obvious, but in countries like Lebanon, Turkey, Venezuela, Egypt, etc. the central bank is quite clearly redirecting new money to favored, politically-collected people and firms. This is straight up theft from their citizens.

Many people say that even moderate inflation is fine, as savers can receive interest that cover the inflation. It's been years since that has been true, and in many countries they actually receive negative-interest for the "privilege" of saving money, which makes that argument untenable. Another argument is that savers can instead find yield to beat inflation by investing. I don't think forcing people to become mini-hedge fund managers, inflating asset bubbles, and encouraging malinvestment in firms because there are no other places to put money is a healthy thing.

Inflation-oriented fiat currencies reward debtors. The smartest play is to have no savings and be in as much debt as you can, as inflation eats away at what you owe and you can typically own some sort of asset in return for that debt. Morally speaking I dislike the concept of a debtor-society like we have in all countries.

Fiat regimes encourage every firm to become banks. Car dealerships aren't in the business of selling cars - they are in the business of making loans. Retailers aren't selling clothes - they are selling credit cards, and the clothes are the loss-leader to get people in front of the credit card seller. Ultimately the natural progression in the fiat system is to take whatever it is you are selling and convert into a loan shark so you can make interest above inflation. That is the highest-value service you can provide in the fiat monetary system.

You said "horrors" of deflation. It is interesting that all computer equipment and services have fallen in price drastically, year after year, since the computer revolution began. There is no other way to describe this except "deflation" in prices of computers, yet this is not a horror and instead people love that prices continue to fall.

People will always need food, shelter, and medical services. I believe they will continue to desire education, entertainment, and all manner of other goods and services and this will not stop in a deflationary monetary system. What I like about deflation is that firms are encouraged to constantly improve their offerings to convince people to part with their money, as savings are rewarded over consumption. It also makes salaries default-drop to match deflation, rather than default-increase which rarely happens in time to match the inflation rate and cost-of-living increases in the current system. I like a system where firms are forced to constantly improve their offerings rather than make them shittier as we do in the fiat system, i.e. shaving ounces out of the shampoo bottles, replacing high-quality ingredients with inferior ones, etc. in order to compete.

In a hard-money deflationary world, equity would flourish and become as advanced as we currently are with loans and debt. As any loan would have to have very tiny interest (perhaps negative interest) to match deflation and entice borrowing, so equity would become much more common as a financing instrument and also align lenders far more closely with those they give money to.

Finally, I dislike how the government's ability to print money enables them to fund programs I dislike, especially the foreign war machine, without making their citizens pay for it. In a hard-money system where governments actually had to raise all the funds from their citizens in order to pay for what the politicians want would IMO drastically reduce the size and scale of government. If citizens actually had to pay for foreign wars, they would not last anywhere near as long. This is a major benefit of a hard-money, "cannot print money out of thin air" system.

I hope this gives you a brief explanation of my (obviously minority) perspective and why I dislike central banks and fiat currencies.