Well, both the methods have their own pros and cons. However, I would support the trader in this regard because I believe that mining is a serious business now and no more a causal activity. It requires high-end hardware and skills to initiate and run the mining farm. On the other hand, trading is based on the skills (and even a basic computer is fine for trading). Since we are talking about something to do in a spare time, I would support trading.
Bitcoin is a digital currency system and my opinion is only two types of the best way to earn btc they are buying and mining ,for mining bitcoin required substantial capital and next thing is to actually invest in btc and trading.