I see the real argument is against poorly-designed MCP servers and where a skill/script would be a better fit.

If all you need is "teach the model how to use an existing tool", then use a skill, or even scripts, which are great for bulk work or teaching workflows.

MCPs are good at giving agents a stable, app-owned interface to a system w/o making the agents having to rediscover the integration every session. There's no way a skill/script would be able to handle the stuff I do via my local MCPs for managing certain apps and databases.