As a consumer, how many currencies do I want to deal with?
How many consumers will be willing to do currency conversions on a per transaction basis?
How many consumers will be willing to do currency conversions on a per transaction basis?
For example take Apple - you have the App Store , iTunes, app purchases, Apple Pay, the new Apple Card and more I probably forgetting. As time goes on, it’s not far fetched to assume that you might rarely leave the Apple economic ecosystem or even need to since everything you have is provided by one corporation. This applies to Amazon, Facebook (not as embedded as Amazon or Apple but has ambitions to get there), and more. So the idea of there being an Amazon coin or an Apple coin, once things mature in the cryptocurrency industry, is not totally out to lunch.
Why have the extra coins and conversions, as a consumer? Even if the companies want to use them like DerpCoin (see Hermitcraft), they will still have to take USD. So will they really ever gain sufficient usage to warrant the company time / people investment into supporting them?
I also suspect most people are involved in many more economic microsystems, which sounds like a business I transact with by another name.
I assume many people here travel (or did pre-covid) frequently and mostly don't even notice the currency that's being used when you swipe your credit card when making a purchase. The details such as whether the merchant gets USD, EUR, or GBP are abstracted away from you and all you care about is buying your souvenir and figuring out where to go next.
When abroad, prices are listed in the local currency, and I have to do some mental math, but yes the transaction does currency conversion automatically, with a fee that is typically higher than I would have realized if I swapped beforehand.
The point is, what currency will prices be listed in and do I have to jump through these mental hoops everywhere I buy things? Unlikely that most consumers will want this situation and extra layer. If it's listed in USD, why not just pay in USD and avoid the conversion stuff all together?
That is why a plethora of currencies will not pan out. It's not a out technology, it's about people's minds and behaviors.
For the buyer they can use any currency they want transparently and for displaying prices things can only get better.
I would call this best case. There would need to be significant (likely unattainable) effort to change the standard. How many laws, signs, and code would need to be changed?