You can actually do both if you are having enough money to do that. Because I can't say that you should just invest in only one because those two investment are so important. Once you invest in real estate it is physical and you have the papers you can inherit it to your child and in bitcoin/btc you can inherit it too.
Investing in real estate can't provide you unexpected income but investing in bitcoin can provide you unexpectedly high income. This is the main difference between these two options. I would select bitcoin investment.
While you are correct that bitcoin can give to you unexpected profits at the same time real estate is not a bad investment at all real estate does not give you profits like bitcoin but if you rent the house or whatever property that you own then you can get very steady profits and the best thing about real estate is that it goes up as inflation grows as well.
Doubtlessly, both are beneficial investments but we are supposed to choose the best one so that a person can make as much profit as possible in short period of time. I also consider bitcoin better than real estate. Nothing can be as profitable as bitcoin is. Saving all the paper work of real estate and other stuff related to it, bitcoin is something that only belongs to holders and it is easy plus simple to deal with bitcoins.