You seem to be responding to an entirely different thread.
Let me restate the argument:
Requiring interoperability promotes user choice and prevents lock-in. Instead of messaging apps acting as walled gardens or closed networks, interoperability allows users on different platforms to communicate, rather than being siloed. This gives users more freedom in choosing apps based on features, design, etc., rather than being forced to use the same platform as their contacts.
Requiring interoperability encourages competition and innovation. Interoperability lowers switching costs for users. This puts competitive pressure on platforms to constantly improve and add new features to retain users. It also levels the playing field for new entrants who can interconnect with dominant incumbents. Overall, this spurs innovation across the messaging ecosystem. It is a defense against being abused by monopoly companies and their lobbyists.
Requiring interoperability improves the user experience, enabling exciting new use cases like unified messaging across multiple networks. Users can manage conversations with their full contact list in one place, rather than having fragmented discussions across disconnected apps. This makes messaging simpler, more seamless and intuitive.
Requiring interoperability promotes inclusion and equity. Lack of interoperability can exclude some demographics from conversations if they do not use all the dominant platforms du jour. Interoperability enables easier communication between all users regardless of socioeconomic status or technical savviness. This promotes more equitable access to digital communication tools.
Requiring interoperability can enables new functionalities and new growth areas like cross-platform payments, multimedia sharing, read receipts etc. Developers can build higher-level services on top of interconnected networks, like AI-based language translation between messaging apps. This could create richer, more functional messaging experiences.
Overall, even though mandating interoperability does place some minor burdens on messaging platforms, the benefits for users, competition and innovation outweigh these costs. This is why thoughtful regulation to require interoperability is beneficial, and the EU should continue to do what it does well - i.e. improve the lives of their citizens and strengthening its democratic credibility, while ignoring the siren voices of greedy corporations and their acolytes.