Some people see Bitcoin as a source of income and they wait patiently for it to grow so they can sell and it profit especially those who are traders, a lot of people see it as there only source of income but we forget Bitcoin is very volatile and anything can happen at anytime one can be expecting to get a huge profit 3 years to come from Bitcoin and Bitcoin falls, this has caused a lot of people depression and it is advised that will use our Discretionary Income to invest in Bitcoin.
Some people says before investing in other business you must make sure you have accumulated enough Bitcoin but that's not it one can still invest in a business that will give you income while accumulating Bitcoin especially for those who are not long term Bitcoin investment.
When you build another business that brings you good profit it will help you grow your Bitcoin more bigger.
Building another business while accumulating your Bitcoin is not a bad idea, and is very much possible, let's all stop seeing Bitcoin as a source of income because it may cause panic when ever there's a dip or fall in Bitcoin.
I'm not sure Bitcoin can be term as a source of income but a source of profits from Investing in it. It can be a source of income for people that trade it and trading consistently give you money even though you might not be making the money everyday and trading doesn't only mean you earn money when the market goes up, if you are professional in trading, you can make earning both means of the market direction.
My own advise is that whether you are making money for real in trading or buying Bitcoin to hold, it's better to have another source of income that is independent on your Bitcoin earning so that when you see unpredictable problems, you don't have to run to your Bitcoin to solve problems, you will likely sell at lower price or better still sell your Bitcoin to solve problem without having another means to buy back and even if you buy, you may not see that price again.