It's argued that the utility of signing a message with a multi-sig address should be akin to that of a single-sig address, enabling users to cryptographically demonstrate ownership of an address. This feature is already available for single-sig addresses, suggesting that extending it to multi-sig users would cater to a niche yet essential user base, including individuals and compliance-abiding companies. Despite privacy concerns deterring the development of such features, the argument posits that since single-sig signing exists, multi-sig signing could similarly benefit a specific set of users without compromising privacy principles.

Further discussion delves into the technical aspects of Bitcoin transaction proofs, such as proof-of-funds and proof-of-sender. The complexity of these mechanisms lies in their need to ensure security and privacy while accommodating the unique requirements of coinjoins and other privacy-enhancing technologies. Suggestions include delegation of signing authority and the introduction of a unique identifier for simplifying signature verification processes. Moreover, the Partially Signed Bitcoin Transactions (PSBTs) format is acknowledged for its potential in improving compatibility with these advanced cryptographic proofs, albeit with noted limitations that necessitate further technical refinements.

The dialogue also touches upon BIP322’s role in facilitating the signing of messages and the collection of UTXO sets for authentication purposes. However, its development has been hindered by its potential misuse for Know Your Customer (KYC) procedures and a lack of interest in its primary utility for pre-transaction contract agreements. Despite these challenges, some wallets have adopted BIP322, indicating a demand for its functionalities. The necessity for BIP322 or similar proposals becomes evident when considering operational challenges faced by entities requiring legal proof of Bitcoin address ownership, especially those preferring multi-sig wallets for enhanced security and governance.

The conversation further explores the practical implications of BIP322’s limitations, highlighting the Bitcoin association's struggles with signing addresses using multi-sig wallets. Applications like "Swiss Bitcoin Pay" and Peach exemplify the operational impact, where legal requirements necessitate proof of ownership through message signing. The inability to fulfill these requirements with multi-sig wallets underscores a critical infrastructure gap within the Bitcoin ecosystem. This limitation not only affects financial operations but also hampers efforts towards decentralizing treasury functions among companies opting for the added security of multi-sig solutions. The expressed anticipation for ecosystem improvements reflects a broader call to action for the development of technologies that enable secure and decentralized verification methods in Bitcoin transactions and ownership.