The indicator of mass adoption is, for example, the announcement of the owner of airbnb about the beginning of the adoption of cryptocurrencies as payment for rent, and this is not particularly significant news, but still has a positive effect on the crypto market as a whole.
These is good that adoption is really happening, there are many ways to use it now and to get access of it, however at these time that price of BTC is rising and is too volatile. I will intend to just invest my money or keep it still as crypto investment than using it, when the price seems too be much more stable in the future and adoption becomes more bigger many industries will use and implement it like a fiat that's the only time to spend it.
For me it is okay to use bitcoin to pay rent because the higher the price of bitcoin, the lower volume it gives. Yes, it has high value and tend to hike even more but also it will drop in time. It is best to use bitcoin like fiat as it is more safe and fast transactions. Time will come where employees going to receive crypto as salary either. Using bitcoin make the demand for it to get higher value.