What implication would countries having their own Crypto have on the wider crypto markets?

Seeing a lot of press lately about countries talking about making their own cryptocurrency - “Britcoin” is the latest offering from the UK (appreciate it won’t be called that) but anyway would this not be a good thing for Cryptocurrency overall? This would usher in the mass adoption we all hope for and I’m assuming once that happens and BTC is rightfully placed as the “gold standard” cryptocurrency would there be ways to link your Bitcoin agains your “Britcoin” for example as collateral?

I’m trying to imagine how this would be a bad thing for Crypto overall as I see it as a huge positive that would affirm the existence of current crypto currencies?