This definition applies to every currency and commodity. It is clearly a very basic statement with wide implications, as anything needs a use case to be worth something. With regards to blockchain, people “using” it at first instance, are the miners. Without a working network there are no transactions, even if there was a demand. Even though Bitcoin is more or less a trademark, in case of PoW coins “use” needs to be assigned to miners firstly and active transferrers secondly .