Bitcoin is mainly a technological breakthrough. So much that it is actually a platform which you can build a lot of useful things with. Think of it like the internet. Except now, you can do stuff which require security and proof in a fast way. Seemse abstract now, but so did the internet seem as well, years ago.
Nowdays, Bitcoin is probably mostly used as a trading currency. But once the new applications roll out to more users, everyone is going to be using it. It’s that big of a technological breakthrough. Bitcoin is also copied to about 600 different alternative “coins” which is where the development of these new application are taking place. Hence, the trading.
All in all, it’s a new, exciting field that has opened up and everyone should have a look at it once and a while.