Whether one should invest in bitcoin or not depends on whether you think Bitcoin will become a long-term trusted store of value.
If it does become a long-term trusted store of value, BTC should trade around $2,000,000 a coin (depending on how many coins are lost and are actually in circulation). That is over 100x the price of where BTC is today.
If BTC does not become a long-term trusted store of value, its likely price will be close to zero (unless it becomes a "cool" collectible... which is a possibility).
So if you think BTC has a 10% chance of becoming a long-term trusted store of value, it is a good investment with a nice expected return. It is still very risky but professional investors should invest some small portion of their portfolio in this case.
Well, indeed. It gradually depends on the perception of an individual if he thinks that Bitcoin can be a good and long-term trusted store of value or not. I bet even Bitcoin users are sometimes thinking of that Bitcoin might be or might not be a long-term trusted store value especially the new ones because of its too much volatility that although a great advantage and a unique characteristic of Bitcoin, was also risky and fearing in a way that "What if one day I wake up, Bitcoin was already down into zero value?" which is a mindset of those people who are too curious that it can be possible to happen. But for us who have already bet our trust into Bitcoin, we are already treating it as a long-term trusted store value so it is possible.