though I have seen some persons who hold without having a good source of income. They operate on discipline because of the trust they've built in Bitcoin but that won't last, when hard times strike he'll be forced to sell his coins. having a good source of income is the first stage to fuel the idea of planning before engaging in bitcoin holding, aside that all trials would be a failure.
I agree with you that you need to have an income source in order to continue to invest in bitcoin, but you might not need to have an income source to start investing in bitcoin, but if you are depleting some kind of funds that you have in reserves or some other asset, you have to be able to realize that you are going to need to have an income source at some point in the event that you are depleting funds, including that you should not be touching emergency funds if you have a way of resolving the matter, and you likely should not be using emergency funds to invest into anything, including bitcoin, unless you have some decently strong confidence that you are going to be able to replenish those funds in a fairly soon timeframe.