Odd-shaped miscellaneous data that you only need to retrieve
is a good candidate for a JSON field. Once you're heavily using some piece of data, or if you need to index it (which means you are heavily using it), you should insert the data in the database "properly".
If some vendor is giving you a list of categories you don't care about, there's no need to make a vendor categories table and a many-to-many link table until you actually need them.
The point is that putting data properly in the database lets you use database features on it and get database performance.
