Why try to crack IMAP?

I believe I have things under control, but was wondering why anyone would try to hack/crack into an IMAP server? I have a server that gets many unknown user' attempts per hour. All one could do if successful is read/delete email messages. Why do they bother?

I've set up fail2ban to jail IPs after one failed attempt...for 24 hours. There are currently 224 jailed IPs...so 224 attempts in the last 24 hours.

Thoughts?