Investing is long-term and involves low risk, while trading is short-term and involves high risk. Both methods can be profitable if the right strategy is adopted.
How big the risk will depend on the knowledge and experience of the investors/traders. Although investment is safer, it can be riskier if we don't have enough knowledge about it. Moreover, if we has a lack of experience in crypto investment. Meanwhile, trading can be safer if we know well how to trade properly. There are many day traders that can gain profits almost every day, they know how to gain profits effectively although the profits aren't really big.
Well, method will be adopted/applied based on the knowledge of the investors/traders. That's why it is required sufficient knowledge to know the wright method/strategy to apply.
Which one is better if I want to invest and trade bitcoins.
Both are good, many people do both investment and trading together. I think we don't need to choose which one is the best.
If we trade Bitcoin besides we invest in Bitcoin, we can get profits daily/weekly. We don't need to wait for few years to get profits. So, we don't feel bored to wait for the profits from Bitcoin investment only.