Exchange rate stability is important. Most people and most companies will continue to pay their bills in fiat for quite some time, probably forever. So, I would want the equivalent in local fiat to not fluctuate too much between exchange and purchase of energy and between purchase of energy and exchange back.
Then, the price of energy does not fluctuate that much for end customers, now. In fact, my provider only updates prices once a year. Would have to be seen if there are advantages for piping the fluctuations of the energy markets through to the end customers. Advantages for the companies so that they would want to even do that and advantages for the customers so that we are really better off that is.
And then there is the question if someone really needs this (as always with crypto currency solutions and enthusiasts always treat this question rather superficially).
Even with fluctuating prices, the standard solution right now would be that I have an account with the wallbox company and pay the balance of my energy consumption (stable or fluctuating prices being quite irrelevant) once a month or so by credit card or bank transaction and do not care about transaction speed much.
The problem is “only” for people not trusting the wallbox company or the bank in between or for people whom the wallbox company or the bank does not trust. That are a lot of people, yes. And they are too often overlooked, yes.
I don’t know if they are really that much in the electric vehicle target group, right now. At least, where I live, I have the impression that electric vehicles are still predominantly for people wealthy enough that they have no problem whatsoever getting a bank account, a credit card and an account at a vehicle energy company.
But that might and probably should change quite soon.
Still, the question is if cryptos are a solution, here.
We could also use traditional government regulation with mandates that companies have to give everybody access to bank accounts and energy at reasonable conditions. Government regulation is a good, even necessary thing if done right.
Cryptos on the other hand are still dangerous. We have a lot of people getting scammed and hacked even here. The exchange rate fluctuations could still bite people that are not only playing with their surplus, but with their very existence, really hard. Do we really think that they are a solution for the unbanked right now? Will they ever be?