1. Even if you were right, that still leaves international transfers as an area where cryptocurrency is superior to the old establishment system.
2. Not all countries have free domestic transfers. The US doesn't. Many of Canada's banks don't offer it. And not everyone is banked, even in the developed world.
3. You give up your privacy when you use the banking system, so if you don't want your payee to know your name and bank account number, you're better off using cryptocurrency.
1. International transfers are only viable between first world countries because technical literacy and access to internet are undeveloped outside those regions and that's all before converting your crypto to spendable money which is inconvenient if not prohibitively expensive outside the first world.
2. The US doesn't have free wire transfers but all major banks offer free instant transfers between other major banks; not a perfect system but fine for the consumer masses.
3. KYC regulations mean you're going to give all of your info to an exchange which have an atrocious historical record with regard to security when compared with banks, but exchanges also require a bank account to convert funds and often to buy them (or at a minimum a debit card linked to a bank account).
Crypto is pretty much always the worst option except in the situations where you have an imperative desire to put a degree of separation between your legal name and a financial transaction.
1. So then you accept that cryptocurrency is better for international transfers in the developed world? Your point about the developing world is really reaching as well: large areas of the developing world have widespread internet access, and there are a growing number of ways to exchange between fiat and crypto in the developing world.
2. It's not free in the US..
3. People can receive cryptocurrency in commercial exchange. It's not just through purchasing it with fiat.
There are certainly areas where crypto has advantages to fiat, and more advantages could emerge as its liquidity increases. I'm really not sure why you're going to such lengths to insist it has no purpose and advantages.
2. Not all countries have free domestic transfers. The US doesn't. Many of Canada's banks don't offer it. And not everyone is banked, even in the developed world.
3. You give up your privacy when you use the banking system, so if you don't want your payee to know your name and bank account number, you're better off using cryptocurrency.