If I get asked where bitcoin get its value i just say "supply and demand".

With bitcoin you can get a fraction of thing which maximimum amount is limited, cant be taken away(unless you are stupid), the system cant be shutdown by governments and you can transfer that thing to anyone if you like. And the whole things runs and operates decentral and checks itself via hashing algorithms (basically maths).

BTC is not a currency, its more a investment like gold. Something you buy and keep for a while. Nothing you buy to buy something with it.