You're free to just depend on ci-info directly if that's all you need of course. The is-ci module does give you one added benefit however: It allows you to run this on the command line:

$ is-ci && echo "I'm running in a CI environment"

But of course that could technically be baked into ci-info. It's just more convenient to use with npx and to reason about if it's a self-contained module

You're asking why someone doesn't want a lower number of published npm libraries on their resume?