Well, for me, it's because crypto is very much more easier to invest in, and one can start with a very small amount of money.
But when it comes to real estate investing, it requires a huge capital to start plus the hideous process involved, this same thing goes for gold and stock market investment, this 3 form of investments are heavily centralized and arent affordable to the common man out there, but crypto's decentralized nature has made it very easy for anyone to get involved in it.