Bitcoin is actually becoming an alternative source of income for the unemployed remotely to make a living. It is providing part time work at home globally to all and sundry and so I agree that it's a source of income.
It's a good source of income if you know how to do it well. If you will make this as your main source of living, just make sure that you can do it. For miners, I know they are making this as their main source of income as for sure most of them already got the ROI. And for traders, I think many are already treating it as their career.