Let say, your task is to eat so you wouldn't die. You are literally asking: "In what situation I should eat banana or an apple?".

Whatever you like or the only option you have...

I never liked YAML because one tricky space can broke things and, well, I used JS much more then Python. JSON is more popular, and many APIs use JSON only.

If you want more, Almighty Google/Bing/DuckDuckGo/Whatever will help you

I think YAML is the best way to go for CI/CD systems.

You write all your test cases in YAML, basically various commands you need split into different sections and boom, your test executes.

In fact, I hate dealing with the UI and clicking buttons. Imagine you checkin code to GitHub and just modify your yml for your code to be deployed to your servers.

I am talking about something like this.

Use YAML because

• YAML supports comments
• YAML supports JSON (you can actually write JSON syntax that YAML can parse)
• github.com/datatxt/awseome-yaml
• github.com/dreftymac/awesome-yaml

Use JSON because

• You do not have access to a YAML library in your chosen programming language
• You are intimidated by the fact that YAML isn't JSON and you are under political/social pressure to follow the herd