Just to serve as devil's advocate here:
Nothing has an inherent worth, unless you postulate the existence of "worth" as an immaterial label, like "soul".
BitCoin clearly has worth to some people right now. They keep buying it.
It seems odd to me that if the utility of anything were a physical thing as measurable as the mass of any physical object that thing wouldn't still have an "inherent" utility/worth. Are you thinking about "inherent" in the sense of have some sort of Platonic existence? That would be a very odd way of using it.
Either way, since utility is unique up to scalling (e.g. Johnny could get as many times of it from a sandwich as Paul does from a near-identical sandwich), at least in choice theory "worth" is closer to having an "inherent" character than otherwise. Though this is somewhat of a stretch because these kind of comparisons are invalid.
Johnny, who is dying of thirst in the middle of the Sahara desert, would get much more utility from a bottle of water than Paul, who is sitting in a bathtub in his apartment in NY. So what's the worth of the bottle of water?
There still doesn't need to be an appeal to anything in material in order to define worth, not anymore than one needs to appeal to something immaterial do define weight in terms of mass. Have the utility of water be proportional to the thirst of the person, where thirst is also a definable physiological state, with "worth" being a scale factor. Thus "worth" would have a uniquely defined value regardless of person or situation.
Or at least that's one way to do it.
Valuations 101, by William Shakespeare.
That worth may fluctuate and it may not be worth something to you in particular, but it has a value.
Cryptocurrencies only have worth because they have demand, not utility. There is not inherent worth based on their existence. This doesn't make them less valuable, it just means their value isn't inseparable from what they are.
But one can always invalidate arguments by taking to them to the extremes. After all, you can't prove anything exists, so how can any of it have inherent anything?
Well, tulips are also quite useful. You can't decorate your garden with Bitcoins...