[dale_glass]

I'm not sure how useful this is, because memory interacts with pretty much everything.

I mean, great: you've validated that the important financial data you were going to write to the DB is correct. But you didn't validate that the OS itself is in full working order. A bit goes out of place, the kernel writes something weird to disk, filesystem becomes corrupted and things explode in a dramatic fashion.

That's exactly why I try to get ECC everywhere these days. I had an old box serving firewall duty until one day it died because it got bumped, a memory module got loose somehow and the resulting disk corruption rendered it unbootable. Applications verifying that their data is correct wouldn't have changed anything.