This is true, but that doesn't mean the currency will actually be better for them. Deflationary currencies are attractive to sellers and employees. They will choose them if given the option. The ill economic effects of deflationary currencies have been demonstrated.
Your phrasing seems to indicate that you believe that market-based outcomes are always ideal outcomes. I think that is incorrect.
I'd be interested to know what you are thinking of here (as evidence). I view that claim with pretty strong skepticism. But I'd be curious to see the best argument/evidence for it.
Of course, the value of the now illiquid currency will eventually become highly volatile likely ending in a crash. Hopefully after this happens several times most people would get the idea that investment in such things is not a good plan.
One point to consider is, that there is a free competition between different cryptocurrencies. There already exists some more inflationary bitcoin clones, and probably more will come. The markets will choose the currency, which they think is the best for them.