It cleans up your log files, that's why I do it. If you run ssh on port 22 your log files with be full of script kiddies with turnkey exploits spamming every IP

It cleans up your log files, that's why I do it. If you run ssh on port 22 your log files with be full of script kiddies with turnkey exploits spamming every IP address they can find. Change the port and suddenly that the logs get much, much quieter. So it's not really a security technique, it's a convenience technique.