1.  Bitcoin's price on exchanges indicates its level of adoption and how much people have supported it.
2.  The price represents what you can buy with it, it's just a way of measuring Bitcoin's value.  With its current volatility you can't just pretend the value has stayed the same, and that's essential when buying something.
3.  Storing value in Bitcoin will be essential in the future because it helps to keep the price stable.
This is just capitalism.  As long as people continue to think there's a "greater fool" to buy it off them for more, there will be more users and eventually this will make it revolutionary again.