What advantages does SLA Breakdowns have compared to the [task_sla] table and metric definitions?

I've come across SLA breakdowns and can see an SLA breakdown can be set against an SLA record, but I'm failing to understand the advantages compared to data already recorded in the [task_sla] table or available through the use of metric definitions.

For example, SLA Breakdowns by Assignment will give you a clear understanding of who worked on the task (and when), amount of SLA time used, how much remains, etc.

Is this not already achievable by using the task_sla table? And if we wanted to build a picture of who worked on a task then couldn't we simply set up a metric definition for assignment group changes?

Perhaps I am missing something obvious, but if anyone can shed some light it would be much appreciated.