Transaction clearing between banks isn't particularly fast, but that's because of legacy legal issues more than it is anything technological. The actual transfer of large sums can happen very quickly.
Most of the things that crypto proponents tout as features (transaction irreverisibility, lack of inflation, etc.) are in fact bugs, and they just don't realize it because they don't realize how finance and economics actually work.
Tapping your watch and wondering "why isn't everyone using crypto already??" is never going to yield useful results, so you do actually need to address these issues.
These are not inherent features of cryptocurrencies, there are cryptos with reversible transactions and inflation.
I always wonder if we were taught inflation was good, or if inflation is actually good.
Im going with the first, because logically I dont agree, but the government kept telling me it during public school.
They weren't bugs for the thousands of years when gold was used.
> they don't realize how finance and economics actually work.
You probably mean the last 40 years of finance and economics, since our modern monetary system has really only been around since Nixon took the US off the gold standard after the US over spent due to the Vietnam war and Charles de Gaulle started to exchange his dollars for the quoted rates of gold.
Inflation in its current form didn't really exist. The exchange rate for gold of a country's currency didn't change much, if at all. The dollar went from $20 per ounce, to $35 per ounce during FDR, then lost the vast majority of its value, getting us to over $1,300 per ounce that we have now.
Physical money requires the person giving it back physically. Crypto currencies have a chain of transactions, you can just send the balance back to one of the addresses it was sent from. There isn't much difference there.
That might save money in its own merit.