Bitcoin is a real asset you can invest all your money and have something good to achieve at the end of the investment that will make you feel happy that you have a huge amount of money with you already. Since we are still experiencing bearish season in the market, showed that you can buy Bitcoin as much you want in this month of September and hold to watch how the bull market will show up for you to make a good income that will make you to believe that you invested on a real asset in the community.
Bitcoin is not a physical asset, you cannot hold or touch it but you can own it and no one can take it away from you. Bitcoin has real value, nowadays if you own 1bitcoin you can sell them on exchanges for fiat.
But what is wrong here when you say we should invest all our money in bitcoin. There's nothing wrong with that if you're willing to take risks and plan your life for the long term without those assets.
All investments are risky, so no matter what you invest in, don't put all your assets in one basket, should diversify and always have a backup plan for the worst case scenario.