Why would you build your own MCP client in a real project?

In most real-world projects, you will either implement an MCP client or an MCP server, but not both. People building applications need an MCP client so their application code can talk to the MCP servers they want to use. People building integrations for a service tend to build the MCP server side. The reason a tutorial might cover both is to show how they fit together end to end. When you understand both halves, you can debug issues across the boundary, design servers that are pleasant to consume from clients, and write clients that are robust against unexpected server behavior.