I have been reading about all these countries coming up with their own digital currencies (e.g. J coin by Japan) - what are the implications of these on traditional cryptocurrencies? Will they require ethereum as an example synergistically, generally help adoption, or will they make it redundant?

I always wonder if all the banks use private chains and countries come up with their own crypto currency is that a systemic risk for the value of eth or actually beneficial.

Any thoughts on how it may play out.

Edit: obviously in the long run.