I do not think that both have equal risk. I think that gambling is more risky than trading. In fact in gambling we totally depending on our luck, while in trading it is necessary that we must have some trading experience, we must also have good trading skill, which are too much necessary for expecting profit from bitcoin investment and trading. Therefore we can say that both do not have the same amount of risk.
I think that both of them do not have equal amount of risk. Skill based gambling is something still unknown to me.
I mean that how could one claim the use of his skills in gambling even if the entire thing depends upon the luck of the person.
No amount of skill can help you to win the bet indeed. On the other hand risk in trading gets reduced with the passage of time after experience and some techniques to set the deal and buying of shares is understood wisely. So, it is better to opt for trading.