The top obstacle to Bitcoin being mainstream is mass adoption. Bitcoin now is mainly purchased off an exchange.
If there was an option to use bitcoin as a currency for paying salaries, and calculating how many bitcoins is worth an hour's job. This would increase circulation.
As long as BTC is pegged on Fiat currencies, it will keep being used as a speculative tool.
With or without an exchange, actually we can pay someone's salary using bitcoin, even though the rate changes, if the policy you take is an instant buy and use bitcoin only for media transfers, it's safe
Employees can get bitcoin, and sell it directly to FIAT, it is very unlikely, but surely there is a service that allows this to happen