For react in particular, lots of the form ecosystem (react hook form) can be directly ported to MCP tools. I am currently working on a zero config react hook form integration.
But yes, MCP-B is more "work" than having the agent use the website like a user. The admission here is that it's not looking like models will be able to reliably do browser automation like humans for a while. Thus, we need to make an effort to build out better tooling for them (at least in the short term)
There's space for both IMO. The more generic tool that figures it out on it's own, and the streamlined tool that accesses a site's guiderails. There's also the backend service of course which doesn't require the browser or UI, but as he describes this entails complexity around authentication and I would assume discoverability.
The bigger challenge I think is figuring out how to build MCPs easily for SaaS and other legacy portals. I see some push on the OpenAPI side of things which is promising but requires you to make significant changes to existing apps. Perhaps web frameworks (rails, next, laravel, etc) can agree on a standard.
The premise of MCP-B is that it's in fact not easy to reliably navigate websites today with LLMs, if you're just relying on DOM traversal or computer vision.
And when it comes to authenticated and read/write operations, I think you need the reliability and control that comes from something like MCP-B, rather than just trusting the LLM to figure it out.
Both Wordpress and Shopify allow users to heavily customize their front-end, and therefore ship garbage HTML + CSS if they choose to (or don't know any better). I certainly wouldn't want to rely on LLMs parsing arbitrary HTML if I'm trying to automate a purchase or some other activity that involves trust and/or sensitive data.
Some middle ground where an agent reverse engineers the api as a starting point would be cool, then is promoted to use the "official" mcp api if a site publishes it.