So, demand for money is demand for things you can acquire with that money. It is demand for access to markets that utilize that money. Necessarily this is demand for one kind of money over another, because you want the things that money can buy and there aren't very many markets (yet) where merchants let you decide which money you want to give them. And when people select a money that they decide they want to have, they're going to select the one that's easiest for them to use to get the things they need, which is going to be the one that others also want because they need to spend to get the things they need and so on. Textbook network effects.

Money is demanded fundamentally because of hunger and thirst. And nobody will turn down more money because it's this magic substance that be transformed into anything they want; they want other things and that's the appeal of money. But yes, uncertainty about the future is risk that can be negated by just having more money. That risk calculation is actually the same math a fractional reserve banker would do to determine how much reserves they need on hand, which is fun to think about.