Bitcoin itself is not a gambling but if you do some actions that are more about gambling, then you can consider it.
This two has been compared for many times, and there's still no correct answer here because it will always depend on your own perception.
For me, Bitcoin is more as an investment asset and not just a crypto currency, again this is my own perception and I'm sure some will not agree on this.
There is standard to things whether opinion different or not and such standard is from majority of the general opinion just as your opinion is that bitcoin is more of investment asset. So trading is not gambling like gambling is also not trading. Many responses here have followed the same line as yours. Trade is a more calculated indices which are futuristic and realistic unlike gambling whose main principles stand on luck and prediction.
I like the way you differentiate the two, bitcoin trading is more of calculated indices, it's futuristic and realistic. While gambling main principles is primarily on luck and predictions. I think that if a bitcoin trader chooses to apply this principles of gambling that is based on luck and predictions, then it somewhat becomes a gambling method, which might not yield favourable results in terms of earnings. Better to stick to a realistic method of calculated indices, as you have rightly mentioned.
Trading is even similar to poker. The most important thing is that if you follow the discipline and diligently study and improve constantly, then you can become a professional. I went through these paths, it is very difficult, but many succeed. That's why I love trading and poker. You will never become a professional in roulette and slots, only you will always lose money there.
The funny thing is that you could just buy bitcoin earlier and do nothing else, and you would probably be in the black. It's more difficult than it looks. But the very thought of it excites me.