Everything to do with "money" is a matter of opinion. It doesn't matter if your money is huge lumps of rock (the Rai), tobacco, shells or bits of paper.
You seem to have already accepted that soverign currencies have no intrinsic value. Indeed you seem to accept that there are some that perform very poorly. Examples that come to mind are the Bolivar and the Turkish Lira.
Now consider why they perform badly. You won't be the first to consider the question. The german Mark provided an example and the Ecconomist Hayek argued that governments really couldn't be trusted to control money. The urge to debase it is just too strong. He argued for compeating private money.
https://en.wikipedia.org/wiki/The_Denat ... n_of_MoneyThe book is available from Amazon or I think as a pdf for free.
Of course if we introduce private money, as he suggested, then the problem still exists of how to prevent it being debased. We could use a commodety that is in limited supply. Gold comes to mind. However it's really difficult to use that to pay for anything over a distance. You need to ship the physical commodity from place to place, with obvious risks.
Indeed the same risk exists with the Rai. One of them sits at the bottom of the sea. Dispite this that Rai is still owned and it's ownership can pass from person to person. How? Well it's ownership is recognised, we would say entered on a ledger.
If things can simply move on a ledger, why does the original object need to actually exist. This is how most of our banking currently works. Banks do not provide wheelbarrows full of notes to solicitors so that they can hand them to other solicitors when a house changes hands. Its simply a change on a ledger of who owns the money and another on the land registry.
Isn't this sounding a lot like the bitcoin blockchain?
Ok, so the mechanism isn't so very strange at all. Now lets address a few things specific to bitcoin.
There is a HARD limit of how much bitcoin can exist. Nobody, private or state, can debase the currency by printing more or creating more electronically and using it to buy their own debt (QE). This isn't true of all crypto "currencies"and won't be true of "Britcoin" the proposed UK central bank digital currency.
It also costs a significant amount to change entries on the ledger. The talk about energy use isn't hot air, it's how a cost is applied. Why make it cost? Well so that the cost of being a bad actor outweighs the cost of being a good one.
It's also decentralised. If, as has happened, China bans ownership or mining (keeping the ledger), bitcoin doesn't disapear.
So, why should you accept payment in it? Well you don't have to assuming that you live in the UK. Now if you lived in El Salvador you would have to be able to produce a reason why you couldn't. Not wouldn't, but couldn't. Of course you could then convert it to US $'s at your bank or at the ATM.
I have a tiny amount of bitcoin. I'm investigating it as insurance against inflation.