Storing spam messages does make sense. If you asked me the number of times when we've sent something to someone, they told us "We haven't received anything", an

Storing spam messages does make sense. If you asked me the number of times when we've sent something to someone, they told us "We haven't received anything", and we answer "Check your spam", and there it is... Checking the spam folder is useful when you know something should be there. It's not made to skim through the junk in the hopes of finding a mislabeled email. And storage is so cheap nowadays that it doesn't make sense to not store everything to shave a few megabytes of space.