[kbrazil]

There could be a major schema change that breaks the contract, but one of the nice things about JSON output is that it allows the creation of new fields without affecting downstream consumers.

That is, if I have a CLI program that spits out a list of IP addresses and one day I want to also output the corresponding dns names, I can simply add the "dns" field and existing pipelines will ignore the field and work just fine.

This is better than grep/awking/etc. unstructured text to STDOUT because, depending on how the author decides to add the new field, it can easily break existing pipelines that rely on the shape of the data to stay the same.