When/If people get to be using crypto to pay for things at Ikea, it will be the same. They won't be using the blockchain directly. They will be using "layer-2" systems. These systems will be more efficient because they can batch multiple transactions into one.
(With decentralized tech, there is also the possibility that IKEA itself can provide banking/financing services separate from their furniture retail business and that people might be using their "IKEA card" to pay for things anywhere.)
For all intents and purposes, it very much is. When I use my credit card to purchase something from a foreign supplier, the current exchange rate is used. It isn’t the exchange rate a few days later, nor the exchange rate when I settle the my account: it’s the exchange rate at the time of purchase.
Further, some cards do settle near immediately: https://usa.visa.com/run-your-business/visa-direct/small-bus...
Now, please explain the “layer 2” solution: on the day that BApes drove wth gas fees sky-high, did layer 2 charges remain stable and low-cost? Who foots the bill for the difference? Is settlement delayed until the price comes back down? What happens if eth gas fees remain sky-high for days?
I'd argue that isn't really "settlement" though. The funds do arrive (which is at least better than the status code), but they can still be clawed back for any number of reasons at that point.
IKEA has already been running a regular bank for years FWIW: https://ikanobank.se/
A short way to explain is that every participant of a layer-2 system locks funds into a smart contract, which gives you a balance in the system. The off-chain system them keeps its own separate accounting and settlement mechanisms, which do not require the blockchain and can be done cheaply. You only need to use the blockchain when you want to withdraw your funds from the layer-2 back to the main chain.
The different systems have their own approach for this off-chain tracking of the funds, but the important characteristic of all of them is that the users are in control of the funds at all times. Unlike sidechains, l2 systems all have mechanisms for users to prove the ownership of the funds and are allowed to unilaterally withdraw.
So if you had just finished shopping at IKEA, which we all know is a time sink beyond compare, and unloaded your burdened cart onto the conveyor, and went to pay … you’d have been dinged by an enormous gas fee or abandon the goods and piss everyone off? Have them hold it for a few hours? Have you seen those lineups, they can’t stash everyone’s crap until gas fees return to some sort of reasonable charge.
That is nuts. Unworkable. I must be misunderstanding.