To be a part of the growing digital currency network, people need to use bitcoin. Bitcoin usage will increase, once more people become a part of the grown network.
I agree with you. I think this is the main reason. When people join bitcoin community and start using bitcoin. The digital currency network start growing day by day.
Nowadays, the number of peoples who use bitcoin start increasing slowly. So, in result we can see in the near future the price of bitcoin will increase more.