It is as if in the Nazi's enigma machine they told you to trust their secure element, a black box of a private company that assures you that it encrypts it and that they can not decipher it, simply because this company says so, and if I find a vulnerability in the secure element I can not say it, I have to continue with a vulnerable machine, I do not think that the Nazis would accept it.

Cryptography has to be totally transparent to know that it cannot be broken, it has always been like that and it is the military method, hence the NSA or NIST for example, make the algorithms public and want them to be used, to be tested.

No one would trust a closed algorithm and even less that depends on closed hardware.