You no go fit call gambling an additional source of income, something wey depend on just luck cannot really be called a source of income. That said, trading dey risky, but e require skills; so it can pass as a source of income, so many people no dey trade because of the risk wey dey am. Personally in the crypto network, i rather hodl than trade and as for my additional sources of income, it has to do with my professional in real life and not related to crypto.