I don't quite understand what you are saying.

As per the article, the advantage of a library over a service is that you don't have the burden of maintaining the said service. How having a thin client and a server helps?

I also don't see how "shoving new options in the dict" can help. From my POV, if the client needs to be updated to benefit from the new features, then there is no way around it, work has to be done. From there, I much prefer having sensible name, parameters, etc. from a library that can be leveraged by static typing rather than a documentation for a JSON API (I know API-as-specs exist but I've never used, maybe that's why I think that).