Mining has to buy software requires a lot of money and paying for electricity also costs money and it takes time to get bitcoin the process is long so I use my money to buy bitcoins and I save I believe the bitcoins I save will be a valuable asset in the future.
Electricity cost is one needed to consider on this since if you live on the country which the electricity cost is so high then maybe we cannot get a good return for mining bitcoin on some other cause and continuous running it will cost high if we choose to select renewable energy to run our operation. So for small time investor much better if they buy bitcoins than mine it because it will give them more convenience since if they push maybe they will just add to those persons who sell their rigs because they didn't see this worthy anymore.