I'm using in production for one of my physical products. The product is a set of 50 printed cards for facilitation. The MCP server can be used by the facilitator to plan their workshop. The reason behind providing MCP is simple: my end-users do not need traditional API, they need something that they can install in their Claude Desktop app and work with the proprietary data of the product. My product's data lives at edge in Cloudflare Workers. (Of course, a determined user can scrap the data if they want, but that's fine.)

Other uses of other people's production MCP I'm using is Dodo Payments' MCP server. It has helped me a ton for looking up their documentation etc. 10xed my OpenCode agent's speed in building payment integration. This was the first serious usage and benefit I experienced of MCP servers.

Reference: My production MCP server: https://www.npmjs.com/package/@sisyphus-consulting/wuwei-mcp