The ‘Try It’ feature generates an API request from your openAPI file.
You can then try the request on your API endpoint, to see if it elicits a successful (2xx) response from your API.
This can help you gauge if other developers (or tools) can easily consume your openAPI file and use it to interact successfully with your API (i.e. no API integration headaches).
Then you can also use the response from your API endpoint, to add to your OpenAPI schema.
I use this a lot to save on time (and errors) building out my API response definitions.
You should … “Try It” 
