Yes. Things that have real-world utility and actually serve a purpose are often considered worthwhile inventions. But this topic is about speculative playthings with no utility, no purpose. Ergo, no value.
Value doesn't require utility. There are many things that have no real utility but still have value. What is the utility of the Mona Lisa?
It's silly to argue that something has no value simply because it has no value to
you.
The question posed in the OP was: (underline emphasis mine)
what concepts are you using to value them?
And what's your opinion on them?
I guess it's interesting to hear what the community has to say.
So I answered with the concepts
I'm using and I gave
my opinions. Feel free to use your own criteria if you don't approve of mine.
I personally think it's silly when some people think certain paintings are "priceless". Where's the sense in that? Clearly I'm just not an art guy.