A cryptocurrency is only one of many possible use cases for the blockchain technology. The potential is huge, and so is the potential disruptive effect to several industries but also to centralized state power.

On the other hand, there already is a speculation bubble and it will become even bigger and will eventually burst - as it always does. Many people want to invest, this attracts many projects, many of which won't be viable or are even scam. However, many of the good projects will not only survive but will become even more valuable once the bubble will have disappeared.

This is similar to the .com bubble, but not similar to the tulip bubble - like the www before, blockchain tech has a high intrinsic value and not only a value which is mostly driven by trades.

Many corporations, large and small, have started to explore the possibilities of blockchain and early adoption is happening at a higher speed and a higher intensity as it did for the www. Even some countries have begun to embrace the technology, e.g. with US states accepting smart contracts as legally binding and a baltic state (I forgot which) providing some public services with blockchain tech (e.g. even notary services, dramatically reducing the costs of these, being way too high anyway, at least in Germany in Austria).

There are quite some good readings out there regarding the potential of the blockchain. I recommend "The Business Blockchain: Promise, Practice, and Application of the Next Internet Technology" by William Mougayar, with a foreword by Vitalik Buterin. And "Blockchain Basics: A Non-Technical Introduction in 25 Steps" by Daniel Drescher.