An open port on a hardware firewall is never good, unless intended on purpose by owner of said hardware (not any company), and the software running behind that port is known well and without any exploitable vulnerabilities.
You have to have open ports on the router, in order to have certain items work properly. If you were to close all available open ports, you would never be able to get onto the Internet, to browse websites, or retrieve files or email.
You can Stealth the port, and that is how it should be. You do also have to have ports open when running a File server, or a IP camera. When a request is made to that device, it should only go to that port, and access only what that port is mapped to on the device from the Router.
Think of port mapping, like following a road map across the country. Some exits may be open, others may be closed, while there are some that state on the map that they are there, but in reality are not. That is how the router works. It is told which ports to open and which to close, but should always be in Stealth mode.
That is why when people state that they did a port scan and found a bunch of open ports. The first thing that comes to mind, is why are they looking for open ports. The second is does the person understand the information they are looking at, from the results that the scan test gave.