You can't just look at one point of view. Many people out there may still not know what bitcoin is, and how it works. Maybe you already know and are experts in bitcoin so you can say it's easy. But it's not easy for people who don't know what bitcoin is at all, its good and bad effects. Big profits and it is undeniable that you can also experience big losses. Not infrequently people just want to play it safe. By not wanting to take big risks. Maybe if the bitcoin price didn't fluctuate they would be interested. So whichever investment is important you can master it. It's useless to invest big and big opportunities but you are not an expert in the field. Just be prepared for you to lose.
That's not the only reason, even if you know what bitcoin is, and what is the potential you could make a profit from that, you still may not end up with the same thing over long period of time. I mean I like to diversify my portfolio so if I have a lot of money (which I don't, so I am all in crypto), I would definitely go with crypto and stocks, and even gold and other assets as well that is just how it is.
There is nothing you could make it a weird stuff, it is just business and buy as many things as you can, ALL things are assets if they have value, trading cards are assets, pokemon cards do worth something I believe, just invest in as many things as possible if you have ton of money, but when you don't (like me

) then just keep it at one side. Many people who like bitcoin and invest in it, still do go with stocks just because of this reason.