You can already see real-time metrics of your tests. An API retrieves Live Load Test Metrics? Why would you want an API that does that while a load test is running? A RedLine13 customer asked for it and it became clear what the benefits would be.
This means that while a load test is running, you can be monitoring the test with an API and initiating actions as soon as some event occurs. Which means you don’t have to spend your time watching a load test run.
You could do this by calling the API from a Continuing Integration / Continuing Development (CI/CD) tool like Jenkins or Codeship. Or you call the API from your code with your own logic.
Here is the Metrics API.