Re: Why does acceptance of Bitcoin has to do with the price of Bitcoin?
The main reason why investors and speculators are buying bitcoin is because they are hoping that a lot of consumers will eventually buy it for the purpose of spending it on goods and services. This is ultimately what will be the demand for bitcoin in the long run (if it is to be successful). Bitcoin is not an income generating asset so investors will buy it for no reason other then hoping for price appreciation, however if the only reason anyone buys an asset is because they hope the price will increase then it is nothing more then a bubble.
Demand can also come from people that want to save in bitcoins, not only from people that want to spend them. Gold isn't valuable because people spend it on goods and services, but because it's considered as a store of value by enough people.
We need bitcoin banks, to get interest on our bitcoins. 
For the moment you can directly invest in some places, like Bitfinex or Dicebitcoin. But we'll have bitcoin banks for sure in the future, and also stock exchanges to facilitate direct investing (well, we already have the Nxt asset exchange).