This approach makes sense when integrating LLMs directly into your application.
However, you still need a protocol for the reverse scenario—when your application needs to integrate with an LLM provider's interface.
For many applications, integrating into the user's existing chat interface is far more valuable than building a custom one.
Currently, MCP is the leading option for this, though I haven't yet found any MCP implementations that are genuinely useful.
There are significant advantages to avoiding custom LLM integrations: users can leverage their existing LLM subscriptions, you maintain less code, and your product can focus on its core use case rather than building LLM interfaces.
While this approach won't suit every application, it will likely be the right choice for most.