Good Christ. Imagine having decided that your price structures should be a JSON file instead of persisted in a database and then thinking that any decision made by that person/team is a good idea.
I look forward to when we see the article about breaking the monorepo nightmare.
Depending on how often you need to change your pricing and how many products you offer, flat files might make a lot of sense.
Sometimes this sort of thing is not a bad idea. If it's a simple data structure that doesn't change very often, you get an admin interface (vi), change tracking, and audit trail for free. Just think of it as configuration rather than data and most folks would think it's normal to do this.