In a typical environment most Audit log records are created by System actions and very few records are from real users. In Reports > Audit log section, when trying to reconstruct the users activity, it's nearly impossible to display only records from all real users (unless you specify a single user in the filter). Those records are buried under a huge number of system actions. This makes the Audit log report completely useless in this case.

In Administration > Audit log, we can disable System actions logging as a whole, but it's primarily intended to save db space.

An option to "Hide system actions" should be provided to make the functionality more useful.