Bitcoin Trading isn't Gambling but Buying Bitcoin is gambling, in the sense that its an investment that could price crash at any time.
I got your points because of the unknowm future after buying bitcoin but, I believe buying Bitcoin is far from gambling. The reason for this is that we can research early, before buying Bitcoin, we have control on when we will enter the market which is pretty logical. Even after buying Bitcoins, there are lots of option to minimize the risk and or completely nullify it. Unlike gambling that we all have only one option but to wait for the result of the "roll" after betting.
Yes, i think we can call it gambling since in the first place we gamble the situation if it is the right or wrong time to trade because we cannot visually project if when is the right time to trade because we always have an fear that what if the coin value will still climb or it will totally down so in that situation we are gambling because we cannot tell what will happen next.