It’s a pyramid scheme and an investment bubble like many others. For the moment it attracts more investment because its supposed value is going up, and that investment causes the supposed value to continue to go up. Eventually it will hit some limit and cease to attract more investment or increase in supposed value. At that point Bitcoin owners will panic and try and sell it all, it will become worthless, and a lot of people will lose a lot of money. We’ll be lucky if it doesn’t trigger a recession.
This is fairly similar to the panic that caused the recession in 2008. These huge financial conglomerates like Fanny Mae and Freddy Mack were making a killing in speculating on and selling, between themselves, large packages of mortgages on real estate that had been missold to the real estate owners and which the owners had very little chance of being able to pay back. The value of these mortgages, and the packages thereof, was hugely overestimated - it was the speculation on them that was actually (supposedly) generating money. Eventually it became apparent that the mortgage packages were worthless and it all came tumbling down.
And again, it’s fairly similar to the stock market crash that caused the American Great Depression in the 1930s. TL;DR: Speculating on the value of things that have no inherent value can produce a thriving, apparently profitable market in the short term, but will inevitably lead to a crash.