I would go for bounty campaigns. I say that because it's just too advanced for me to do mining. Also, I don't have the capital to set up mining rigs whether via phones or via computers that can be profitable. Nowadays, the difficulty of mining cryptocurrencies has double from where it was before, and so, it won't be as affective to just have one rig. The amount of capital that you need to just build one is already that much, not to mention all the other factors you need to consider to keep it running, are rather costly as well.