Practical advantages of EDAC

The types of fault which go unreported when you aren't using the EDAC subsystem are often those which produce strange instability in systems (e.g. file corruption, random crashes etc) - these are amongst the most frustrating, and time-consuming problems for sysadmins to track down.

Differentiate between different types of fault.
Spot brand-new faulty hardware before it's put into service.
Spot failing memory modules before they go bad (replace at your leisure, not in a panic).
In a redundant cluster, or a system in which data integrity is critical, you can take a machine out of service before data corruption occurs.
Know which memory module or PCI card to replace (the alternative is trial-and-error component replacement).