We all know that Bitcoin is one of the best ways to invest your money. However, we know that Satoshi wanted to change money as we know it rather than new investment model.
I think these are two sides of the same coin. Remember Satoshi's message from the genesis block -- a reminder of the bank bailouts and the threat they are to the integrity of money. Sound money is both an investment and a medium of exchange.
How do you think, will we be using bitcoin as payment system? Or it will stay as it is and this bubble blow up one day?
There will always be demand for robust, censorship-resistant, permanently stored public payments and data. For transferring lower value, I think that the Lightning Network (payment channels) will serve our needs well. Even if it turns out to be a hub-and-spoke model, it'll still be
trustless. Since confirmations aren't required for LN transactions, fees will be much lower. Satoshi had payment channels in the original software, and now that we have addressed transaction malleability, we can start using them.