Thanks for your feedback. The onboarding pages are currently being improved to better communicate what you are ‘getting into’ when creating/publishing a build scan. This will go live within the next few weeks.
The build scan service available at scans.gradle.com is for free. We also have a commercial product called Gradle Enterprise that ships with its own on-prem Build Scan Server. It is used by various companies that do not want any build data to leave their company.
What exactly we capture will soon be described on our onboarding pages, too. For now, you can find the list here.