I don't think cryptocurrencies will disappear. Cryptocurrencies allow you to make very cheap and fast payments between users. This is a real benefit that is in demand. Bitcoin and major cryptocurrencies will not disappear
I think so too, it is very impossible that cryptocurrency will disappear because it is a the fastest mode of payment by far between user, wherein you only need minutes for you to see the transferred amount to your account unlike with wire transfers that may takes 2-3 business days depending on the bank. Cryptocurrency has a lot of good uses and I think people wont stop using it.
I also agree. Crypto is being used everywhere and it takes major time to demolish it and make it disappear in the network. Though it is not possible that might happen, but the longer it exists, the more people get involve into it and find it easy to transact and more faster than usual remittances.