Yes, json and php for performance are essentially the same.
I generally create some type of assets folder where I keep things, like json exports. I’m also something of a digital pack rat, so I never throw anything away or delete anything that may come in useful. After needing to rebuild a few field groups in ACF manually by reading the php it didn’t take me long to realize how important a json file of a field groups with a hundred fields was to keep around.
