filecoin is not BTC. BTC does have an inherent value, but only within the system. You're analogies to diamonds make no sense because diamonds are easy to produce and their cost does not reflect either the demand or the production of them. BTC, however, is required to actually run the system, are hard to produce and their value is set on their limited production plus demand. It is true that BTC currently has little value outside of the system, but that is not the same as saying it has no inherent value.
BTC does have inherent value if there exists a class of transactions that cannot be settled in any other form of payment.
Extortion where the extortionist demands payment in bitcoin fulfills that predicate.
Not saying that this is what drives the daily ups and downs of BTC (or rather: ups and even more ups, recently), but if you are looking for inherent value, this is what you get. Just like the use of gold in manufacturing is very much not the driver of gold price fluctuations, despite being the base of the inherent value.
