Since port numbers are a very tiny space, that would amount to an infinitesimal increase in security, right? Essentially, 'hiding' the port is 'security through obscurity' which is a thoroughly discredited idea.
This is assuming that someone is specifically targeting your machine. In which case yes, changing the port number probably won't do much. But if someone is just hammering random servers on port 22, changing the port number is much more likely to be effective.
Changing the port does nothing against targeted attacks and it's not about 'hiding' anything. The purpose is to take your host out of the scope of automatic scans which almost exclusively focus on the most common ports (22, 2222, 22222 ...).
