Gold is the same. It's a piece of metal. There is industrial usage for gold but it's minimal compare to the number of gold being stored underground in central banks for storage of currency value. Most gold is used for storage of value or jewelry.
If you want to argue bitcoin doesn't worth anything. What makes diamond worth anything or any fiat currency?
Bitcoin has value as long as it able to provide a service (money transfer) to a community. And as long as the community of people willing to exchange Bitcoin into physical goods and fiat currency (which is just another exchange medium - worthless if you can't buy food with it), there is value to Bitcoin.
Much like the chips you buy at the casinos, those are plastic chips with ZERO value. What makes them valuable is the community (casino in this case) willing to redeem them for fiat currency- which can further be exchange for goods and services.
Of course, one can always make the argument and say if the community abandon the idea of Bitcoin has any value then it has no value. Same can be said of gold or US Dollar. Just because gold and USD are widely accepted now doesn't mean people cannot abandon them in the future and just because Bitcoin has no industrial value doesn't mean it has no economic value if it allows for transfer of funds anonymously. As of now, the community and acceptance of Bitcoin is growing, so the value is growing. Can Bitcoin loses value to zero in the future? It can. But so can gold. It just gold has a lesser probability because of its historical usage in the world. If people stop investing in gold and stop believing gold as a storage of value - the prices of gold can easily crash just as well.