[JPLeRouzic]

You did not tell what is this "other purpose", but you might think about cryptography. Entanglement enables a mechanism where a secret key seems to exist only when it is activated from another location.

That way a satellite would be preloaded with hundreds of "hidden" secret keys and one of them would be available for encrypting only when it would be decided on the ground. A quantum twist to Merkle's puzzles.

I am not convinced by this kind of quantum cryptography. I am sure it would be possible to crack it, because all cryptography proposals are overly complexifying a little aspect of a much larger problem, and someone just look at another aspect of the problem and easily defeats the proposed cryptography scheme.

It is a pattern that we seen an incredible number of times, when do people will recognise it and adopt a more humble, honest and safer way to implement security?

Indeed I am yet another random guy on Internet, I am not versed in quantum cryptography, and I did not work on cryptography since a long time. But on the anecdoctical side, 12 years ago I had to work on identity/security and at that time when I told my colleagues that public cryptography was no more safe, they were baffled. For them it was pure non-sens, yet I could crack (factor in prime numbers) simple keys on my little laptop and RSA stopped a few years later their famous RSA challenge [0]...

[0] https://en.wikipedia.org/wiki/RSA_Factoring_Challenge