Either source of income or investment plan, it depends on the one that’ll work for you when you look at things from different perspective. Seeing it as a source of income depends on the work you’re doing and being paid in BTC. Only some crypto related companies will pay their workers in BTC today since the risk involved in crypto trading is limiting its full adoption by all yet. It’s okay to work and be paid in bitcoin, it enhance its adoption in some ways too.
If I'm working for a crypto firm and I'm being paid in Bitcoin that does make Bitcoin my source of income, it's the job that I am doing that's my source of income while Bitcoin is the medium of exchange for my services.
Bitcoin as a source of income or as an investment plan, which is better?
I think Bitcoin mining and trading are the two ways we can see bitcoin as sources of income. Bitcoin as an investment plan is the most popular and it means one needs to buy and hold to realize some profit. Which ever one might settle for is dependent on the person's pocket and knowledge and It's hard to say which is better. In the case of mining, you would need a big capital to get your miner, cover installation cost as well as electricity. Trading is not expensive, just the right skill set and small capital should be enough. Investment requires proper knowledge of the market and capital.