In public regarding cryptocurrency so most of the people think cryptocurrency is a bubble but it's not a purple cryptocurrency is going to stay here, and it is going to change our life blockchain, and cryptocurrency will be used more and more even some of the governments are planning to create their cryptocurrency and use it.Blockchain is the Technology behind cryptocurrency I will take a simple analogy to explain what is blockchain and what is cryptocurrency all offers no email and internet without internet we cannot send email similarly without blockchain we cannot have cryptocurrency so based on blockchain technology cryptocurrency works.
I don't think all cryptocurrencies are in a bubble right now but some are though some older ones are undervalued