I'm part of the application development team comprising 10-12 developers and I have used GitLab for configuration and version management. We have also used it for DevOps, but I have not been involved in the DevOps side. My work with GitLab involved basic version management (i.e. checking in, checking out, merging) and related features.
I have also used GitLab for doing remote builds, which is when you check in and it triggers the build on the application remotely. For example, we have a YAML script that has been written for performing builds on GitLab automatically and when that script gets executed, it performs the builds and copies them to the destination folder. All of this gets triggered from GitLab.