I don't think any blockchain technology accomplishes anything that couldn't also be accomplished with a trusted third party. The innovation, if you see it that way, is always in doing things without any trusted third party.
Additionally, your response is in the context of the question: "How does Ethereum help with retail?". Your answer is "it helps to avoid erroneous charges", but that doesn't answer the question of why Ethereum is a compelling option compared to a system that has already solved this problem without the inefficiencies of the blockchain approach.
Here's an specific example, and certainly not the only one: I sell a digital good valued in $20k and I don't need to give paypal $580 (2.9% fee), it can be accomplished with $0 fees with the same level of trustworthiness. You just got rid of the middlemen...
Now multiply this sale for 100 articles my store sells daily and you'll begin to understand why this is so powerful.
$20k subscriptions in finance (like a market data live feed) are not only common but even cheap. Now ask yourself why Wall Street is so much more hyped with blockchains than SV...
> You can very easily end up paying a similar price for conversion surcharges and unpredictable daily price swings
You don't have to pay with ETH, you could do things like peg your ERC20 token to the USD, 1 of your token = $1, the underlying asset (ETH) can do whatever it wants with the price, your tokens are decoupled from its value. The monetary policy is up to the party that issues the token... Remember: this is "programmable money".
I'm not saying $20k digital goods are non-existent, I'm saying that they're an extreme niche that does not reflect practical reality for the vast majority of businesses.
> Now ask yourself why Wall Street is so much more hyped with blockchains than SV
Because SV is more often composed of individuals with a deep understanding of technical topics while finance is more often composed of people who are less knowledgable on these topics and more susceptible to buzzwords and hype (not that this doesn't exist in SV, but it is even worse in finance). This is evident by the fact that nearly nobody in finance is using blockchain tech outside of experimental research and buzzword bingo (unless you count crypto gamblers and traders).
> you could do things like peg your ERC20 token to the USD, 1 of your token = $1, the underlying asset (ETH) can do whatever it wants with the price
Except that this is even worse than Eth because arbitrary custom tokens are of questionable liquidity at best and impossible to liquidate at worst.
Also don't forget that digital goods include stuff like "subscriptions"...