Actually there are many reasons to have BTC. But very important reasons I am going to mention below -
1. Bitcoin is the biggest invention of this century
2. Bitcoin is decentralized, Open source, Secure and Transparent
I think these two reason are sufficient to have BTC. But still price matter. Day By Day price of Bitcoins increasing exponentially. This can also be good reason as Investment
Its usability to the people and the great opportunity for the investment as it provides the highest return is what is attracting the people across world to invest in the cypto currency. Thus more and more people are getting connected and want to be part of the biggest invention of the recent times. This is something if approved by Central banks or some of the highest authority will boost it and create a new dynamics of the virtual currency.