Mining wallet? Well that's a new one lol. I haven't heard about such, it seems you must have been mislead because nobody mines bitcoin with phone and definitely you can do it alone, if that was even profitable (mining on phone) then you'll be doing more harm to your device than actually participating in the mining industry. People don't talk much about mining because that area isn't for everyone, you will need to have some level of skills, information before you can record successful unlike other area that a noobs can get hold of them within days or weeks of participating like trading and investing.

For me the easiest has to be investing, there's no risk involved if you know what you're doing. Trading cones with risk as every market you enter stands a chance of rekting you irrespective of you been a professional trader