This kind of forms are the way on how earning a bitcoin. Though every form has its own different ways and different level of risk. Yet all this kinds give credits.
Yes every form has their own different way and level of risk but you should mind it that it has also their own earning of money and every way has give to people a lot of money so that's why it called digital money or currency because it has a lot of opportunities to make big amount of money in very short time, so people should keep trying every way of this currency to make money and buy this currency for best future planing because this currency will increase in coming future and you could get best profit.