There are lots of coins this days and more are still emerging by the day. If eventually cryptocurrency becomes accepted globally and it's been adopted for usage, do you think all the coins would be accepted for usage or only a selected few?
Not all of the coins, there are a lot of the coins that are practically useless and there is nothing that they can be used for, that is why a lot of the altcoins are going to end up dying out, What will happen is that the coins that are useful and can be applied will be the coins that actually get used widely and there will be coins created by each country
About the coin you find useless, there are a lot of altcoin was born when Bitcoin for the first time reached the $ 1000 price. I could for example be a very manipulated altcoin in 2017 as RDD, it originally had only 2 programmers. When I knew it it was only worth 1 satoshi and did not know what it was used for