It is the best if people can manage both of the things if they have time as you would make money in both ways if you can trade well and also this can become your full time job as well and create employment for others as well if you do well in trading .
Maybe best is to have all 4 combined. If someone is mining for quite a while for example, then he is active here on forum he can get maybe about here to pay bill, see some insight for trade and if he want to gamble we have many topic here with some good tips and predictions. So maybe best possible option is to have all combines but it takes time, effort and money invested.