I think a lot of the applications that they talk about will be built in such a way that people won't really know or care about the fact that its decentralized, or exists on a blockchain. Much in the same way that a lot of people don't use the "internet" but use Facebook every day. They don't care about the underlying tech, they just want to see funny pics or talk to their grandma.
Right now, cryptocurrencies are in the "Usenet" stage, where most of the users are tech enthusiasts. Eventually they may get to "Facebook" stage, and you're right, most users won't care about blockchain, but they'll still use it.
It will cost an order of magnitude more to run the app on the blockchain, just like it costs an order of magnitude more to have a decentralized ledger instead of a centralized ledger for accounts. There remains no useful application that justifies the cost, aside from malware monetization and other illegal transactions.
It currently costs more than $2 to transfer Bitcoins. It's free to transfer money to people in the same country off the blockchain, and the transfer confirm is faster.
$2 is less than the cost of an international wire transfer, especially if you live in a country where people are restricted by laws from making such transfers. But in any case, Bitcoin has reached its transaction capacity and transaction slots are scarce. Simple payment transactions on Ethereum currently cost less than $0.05 on average.
Domestic money transfers, which make up the bulk of the transactions that people care about are free and instantly confirmed with existing centralized ledgers. Why should people waste time and money using a distributed ledger when the existing system works better?
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.
Right now, cryptocurrencies are in the "Usenet" stage, where most of the users are tech enthusiasts. Eventually they may get to "Facebook" stage, and you're right, most users won't care about blockchain, but they'll still use it.