Cucumber frameworks work excellently for pair programming, end-to-end testing, and any sort of testing that is best communicated with written instructions and is understandable for non-technical people. Once a step has been implemented, it's generally possible to reuse it wherever it's needed. If you want to test integrations between services, tests can be written to use actual HTTP clients if you first ensure that your environment is set up to receive HTTP connections.
The datadog implementation of behavior-driven development (BDD) is lacking a few features that you might expect if you've used other Cucumber frameworks, including lack of examples, passing a context between functions, and a number of other keywords. However, it's a good start, and by using a few tricks in this recipe, such as globals for tracking state (and ensuring that you clean up those globals between scenarios), it's possible to build a fairly robust set of tests. The datadog testing package also uses a third-party test runner, so it's impossible to put it together with packages such as gocov or go test -cover.