Proof of ownership or proof of reserve for individuals/companies

[Perfectbaby]

with your concept there is no anonymity over there anymore that is to say that bitcoin is no longer following it's decentralized nature because if that is being implemented your bitcoin address is on watchlist and everyone could view and look over your asset to determine if you are the sole bitcoin owner or not this same thing also given government the edge to monitor over people's assets in their custody since there would be a verification and authentication to show that you are holding a specific amount of bitcoin in the address that is being verified and signed a message on.

[retreat]

Trusting a third party to prove your Bitcoin ownership might be a pretty stupid idea, because while you should protect your privacy when you own Bitcoin, you instead prove it to another party just to get a loan. It's basically like allowing other people to know your identity, and you don't know what they will do to you if they find out you have Bitcoin. It is better to use other assets as collateral for the bank compared to the Bitcoin you own.