$20 transaction fee. Bitcoin for small payments is dead.
It should be a medium of exchange, but for now its a speculative gamble.
With bitcoin in the example I gave earlier, the only currency required by both local exchanges would be Bitcoin, simplifying.
Technically this use is still likely to be illegal.
And bear in mind, my original point is that bitcoin is moving away from the original intent.
For that $2 a transaction is forever recorded on thousands of nodes in a worldwide consensus network, secured by a huge number of miners. Blockchains are not going to scale to visa level numbers of transactions without huge blocks and de facto centralization.
The reasonable alternative is a second transaction layer, the lightning network.
Bingo. Short of it is that consumers don't care. They just want to be able to buy something and have the transaction complete immediately. Whether it's a central payment network, a distributed consensus of 1000s of nodes, or a single "ring" from an in person cash register it's all the same.
At which point, why not use those same layers over USD instead of over bitcoin?
* They don't transact bitcoin.
* They don't transact your (non)bitcoin in a decentralized way. They alone run the software and are in control of changes and restrictions, including who you're allowed to send to.
* You don't hold the private keys to your (non)bitcoin when it's a bank or VISA or Paypal. They own it for you. They can lock your account and maybe give you the privilege of putting yourself through some asinine process to regain access to it.
The lightning network is a "second layer" that still is decentralized and puts users in control of their own funds.
Check out the asymptote: https://estimatefee.com/
That's where traditional electronic payments have a huge edge -- instant, incredibly cheap guaranteed verification.
Which means it's a gamble if that will ever work.
The protocol doesn't matter, mempools aren't validated or shared[+], and so the validity of the chain isn't challenged by processing the higher fee.
So given that the bitcoin network is designed to be operated by greedy miners, surely one would break with "tradition" and process the second?
You might have to dig to find a route to those nodes but it should surely be possible.
[+] They're not shared as in shared-state, i.e. sync'ed.
But it's playing with fire to rely on that, because without opt-in RBF it's far from a sure thing.