The currency is a kind of currency to which it can spend the people buy food and clothes . And many more things . The property also has the things that you own that you can buy or keep worrying . Such as house and land is your property that can cause to your future children . Because the currency finds that even if you do not have a property if you have money you can buy it.
Well you can invest both in currency and property but the point is that if you invest in property you do not have ready cash in you hand, and if some emergency situation arises, then you will be not in a position to handle it, even though you have the amount stuck in property. But investment in property is still a better choice.