I believe strongly bitcoin will be our future digital currency because many large companies have accepted bitcoin and they are also investing in bitcoin. Moreover, there are countries that accept bitcoin. We just need to be patient and as time goes on bitcoin will be more and more liked by everyone.
bitcoin will be able to achieve that, bitcoin will certainly become the world's digital currency, because every country also creates a lot of local digital currency, but will not be able to beat bitcoin because bitcoin has the advantage of not having regional limits and speed between countries, which is not capable of being done by local digital currencies.
it takes hard work even though many countries have openly recognized it as a legal currency like their fiat money, but it's good to keep bitcoin running according to the advantages it has, but let fiat continue to run to do backups if bitcoin still can't be used in the country In certain cases, bitcoin and fiat need each other so that cooperation can be built.
I wouldn't say it can't be done with national digital currencies to create a network that let's you send money within no time across the world for an almost zero fee. Technically, it can be done. It does already exist for the Eurozone, the so called SEPA network. You can send for a fee money to any country in the Eurozone within 10 seconds. Bitcoin has other advantages than being borderless when it comes to transactions. It is also borderless when it comes to taking your wealth with you because nobody knows.