Blockchain brings a new concept of financial system to the world. It represents a new kind of organization, where there isn't a central authority or institution behind the currencies controlling them. In other words, it could be the evolution of the financial system, so you should care for it.
Furthermore, blockchain is awaking the interest of all kinds of people, so there are big chances it will be implemented in different areas of our societies.

And you should buy bitcoins because it's a serious currency that has already conquered the market. In more than 10 years many haters told it was a ponzi, a bubble and that it was going to die, but in fact, bitcoin did rightly the opposite and came back stronger than ever.
As was said, bitcoin is a great investment and its main potential is on long run, so it can be a precious opportunity, like it was for those who started using btc on the early years.