Everyone is talking about ROI. But that isn't why people are 'mining' , it is mainly for profit - with few exceptions of people who are just interested in the workings or want to support a coin (not applicable in GAWs case).

Why not just buy bitcoin and give it back to yourself after 4 months?

What is more interesting to see is how much you will continue to make after this ROI period. How much will you have lost due to inflation and time-value of money?

Do people think they will make much on top of the ROI? So much more that it is worth the risk or not even returning your investment?