For Home Assistant, the MCP can enable the LLM to make changes without using up excessive tokens.

For example, the only way to make a change to an HA automation via the API is to POST a whole new copy of the YAML, even if changing one things. The skill and HA MCP I use allows the LLM to use tools which make more precise changes without excessive context usage.

Certainly still works either way though. And of course your LLM instance could just roll its own tools to do the exact same thing.