Benefits:
(1) You only really need to know the system as a user, not the codebase as well, to do this.
(2) Well, #1 was a bit of a white lie. You'll end up finding out about all the (possibly undocumented) runtime dependencies this way, spinning up throwaway VMs and databases, etc. If the project is in production, this will be very useful knowledge, since you're probably the last point of escalation for strange prod issues.
(3) Running this out of CI with throwaway VMs/containers will also force you to fully automate the install and make the damn thing actually work on a generic blessed OS configuration, which might be a huge boon to your team if you currently are in "Works on my machine" hell. I did this somewhere where we had tons of lost productivity because developers used OSX or Ubuntu on their workstations, but prod was RHEL, and the most fascinating deviations would be found by developers chasing the strangest of bugs. Making the install reproducible so we could have CI totally ended this.
(4) If you don't have this already, and you set up infrastructure to gate commits on this test passing, team love and productivity will rapidly go through the roof as suddenly your developers aren't spending half their time fighting each other's build breaking changes.
So yeah, it's just one thing, but it leads to so many benefits it's definitely where I would start.
EDITED: Added an item to the list
Of course you can ask people who are more familiar but whether you end up helping or being a distraction then is an open question.
Ask on your team's IRC channel.