People use bitcoin because they want to earned income or additional salary also people wants to use it as preparation to the future currency usage.
From the title of the thread, you are using the present tense while the question is in the future tense, by the way bitcoin has a high price, that ia right, and we all know that it pumps and dumps but still it give profit to users, so I think that is one reason. Another one is because will be widely used by the world in the future so you will be a part of it earlier than the world do.