JSON in the repo also risks introducing customer data to git if you want to rollout based on specific customer attributes (sometimes, for us, it's a list of early opt-in customers we have meetings with to discuss/develop new features)
It's also less accessible for "business users" like product/project managers, sales, and marketing they want to coordinate feature rollout with other business initiatives (and don't want to bother engineers when they do)
Often problems are more complex than they seem at first sight and I have found it’s a good approach to think “what am I missing” rather than “lots of people must be making very obviously bad decisions” and reach the latter conclusion only after more work. Usually I’ve missed something.
If it were that easy people would not be paying for it.
We're a small company but new feature release for big features is typically targeted at low risk users/customers first. That usually means a few attributes are taken into account (age, customer value, customer sentiment, which features they use)