I am not surprised that so far, out of 16 votes 15 say this is an additional source of income and only 1 says it is their only source of income.
Am currently working for crypto full time right now; I earn from my signature here in this forum, am currently working for two crypto groups as a moderator, and am being paid on crypto; plus and minus those three jobs' pay is enough to pay all my bills, that is, if I want to let go of my other sources of income. Earlier before now, I managed a cyber cafe that was giving me huge earnings. I am proudly the owner of one, but I barely visit the place because I spend most of my time on my crypto jobs because they give me the highest pay.
I don't know if you were the one with the only vote, but in any case if you are an owner, you will have income from it, and crypto is not your only source of income. I agree with the other comment:
I think the poll misses one other option, Crypto is my main source of income.
There is an important difference between it being the only source of income and the main source of income.
In any case, to have crypto as the only source of income, I think it usually only happens if you had activities related to cryptocurrencies as an alternative source of income and you lose your job, or if things are going so well with crypto that it pays to dedicate yourself to it alone, which is not usual.