One would assume that Visa (yes they already announced support of crypto) etc transactions would be off-chain, so network transaction rate isn't that important.
Says who? You've just ignored the trustless part of cryptocurrency, what are you left with?
I get the hypothetical of why [cryptocurrency of choice] could be useful, even if I don't subscribe to the idea of a trustless society functioning.
But if you sidestep the one thing it's laboriously designed for (trustless by PoW, or stake/other), why even bother?
I don't have to sidestep it forever and ever since I buy lunch via VisaBTC. And me buying lunch changes nothing about me receiving funds.
The only selling point of bitcoin was that everything was recorded and immutable, and thus volume was transparent. If all of these transactions happen outside of the blockchain (until later, maybe) you can fudge around with trading volume, and game the market, which exchanges have already done.
You are literally just describing banking as it has existed forever, but with less oversight.
I am describing banking without the issues of banks. No need to have a headache because my transaction from Iran to EU is lost somewhere in between without any traceability whatsoever, etc; no need to have a headache because the receiver didn't realize it'll cost them $100 to receive money internationally, etc; no need to think about the hardship of pulling my own money out of the bank while I'm not in my home country, etc...
Then there's smart contracts - show me a bank that supports it? Show me groups of banks (because not everyone has the same, right?) that support it among each other?
> all of these transactions
Again, that's your mistake. That most transactions happen off-chain doesn't mean all or the important ones do. And it also doesn't mean there aren't cross off-chain network transactions - e.g. VisaBTC to MCBTC needs a blockchain to happen in a trustless way. Trust is easy when it's Visa to MC but not so easy when it's EU to Iran banking system.
> You just trust the end result to be accurate
Hahahaha, good luck in Africa...
Doesn't matter if it's all, just that some can be. The issue is that the transaction ledger and the "currency" or asset is the same thing. That exchanges or Visa et al are implicitly trusted with out-of-blockchain transactions means that there's no longer a natural relationship with the finite number of BTC or the veracity of the blockchain. You have just started outsourcing trust again, which IMO is fine, but why the rodeo then.
Pick a lane, you can't have both. It's no longer trustless if you try to do both, at least not on the (speculated) asset value level.
I am going to prefer on-chain BTC transactions to make international business transactions in thousands of USD.
I don't need the full force of trustlessness to buy my lunch - the risk to me is that I get a free lunch. Yeah I could use a classic payment card - but then I'd have to keep shuffling my funds around and that's not fun.
No you don't. You have a speculative asset no longer bounded by the designed limit of BTCs, where banks, i mean exchanges, can create volume out of thin air outside of the ledger, as long as something is later cleared on-chain. Ergo, back to square one.
[1]: https://cointelegraph.com/bitcoin-for-beginners/what-is-the-...