Part of it is to track and fix the occasional bit flip. Said flips can cause data corruption, crashing processes, and crashing machines. However it's also ver

Part of it is to track and fix the occasional bit flip. Said flips can cause data corruption, crashing processes, and crashing machines. However it's also very useful to just know when a particular failure causes issues. So you know that the 3rd of 4 dimms died, instead of tracking down frequent crashed that might be power supply, motherboard, cpu, any dimm, etc. Linus Torvalds recently lost time thinking he had an unreliable kernel when a 2+ year old dimm just went bad.