+1 to dwanthny. Potestus you seem to be confused about what this plugin does and what the Goodreads Sync one does, and this is the second time today you have posted questions related to Goodreads Sync in this thread. I moved your other post to the correct thread here
earlier today and tried to respond to what I could from it.
This Goodreads Metadata source plugin is only concerned with reading book metadata from Goodreads - stuff like genre, tags, title, author, isbn and covers etc. It does this by scraping data off the web page that you see when you drill down to a specific book.
The Goodreads Sync plugin is about synchronising with your shelves on Goodreads for your own Goodreads account. Some people use their "shelves" as genres, so it has features which are an alternative way of populating a genre/tags column if you used it that way. That is perhaps what you are confused about.
The two plugins are completely independent - the configuration files are not shared, the mappings are independent etc. Provided you followed the instructions above exactly and replaced only the "Goodreads.json" file as mentioned on this thread it will have had zero impact on your usage of the "Goodreads Sync" plugin (which has it's own "Goodreads Sync.json" file).
Now that Goodreads have got a "better" solution to displaying genres for a book (which is a recent thing only in the last month or so), my personal opinion is that getting a genre into your tags using this metadata source plugin is the preferred approach rather than creating your own genre shelves on Goodreads. However it is up to users how they want to use their Goodreads account - if they want genre in a custom column rather than tags, if they want their own genre shelves (or already have them setup) then the functionality is there with Goodreads Sync for them to use it.
So... I suggest you first get clear in your mind which plugin you are using and configuring. If you are downloading metadata using ctrl+d or the edit metadata screen, it is the Goodreads Metadata plugin in this thread. This has nothing
to do with your Goodreads account or your shelves.
If you are using a "Goodreads" right-click menu action or toolbar button with acrtions on it like "Sync from shelf" etc - that is the Goodreads Sync plugin. Any issues related to that belong in the other thread.