Banks may eventually play a role and give the option for customers to have Bitcoin with them. I'd assume mainstream folks that have trust in their banks would prefer this. Sort of like an exchange but integrated with existing bank accounts. The rest can use wallets with private keys.
BTC market has many holes, high risk, if set up a BTC may business failure, I think so, the BTC price fluctuations over time, increasing in the future. Currently no one dares to raise capital by BTC.