If its being unpredictable whether you will gain or lose is considered to be a gamble, then I would agree that investing on it is a gamble.
I have been investing my time and effort in accumulating crypto coins. Although not sure if it will be always worth it in the end, the process or experience dealing with these coins is somewhat useful for future dealings.
When investing, I believe in the sayings, "do not put all your eggs in one basket" and "only invest what you are willing to lose".
There will always be risk so better that we have backup such as having some savings or multiple investments.