Port forwarding can help those who needs to do basic stuff not dependent on specific ports to be open. As a start, CCTVs can work. If any specific port is assigned to me at all times than, whatever is my public IP (which is also shared by multiple users) combined with that port can be used by me. A hit on that public ip with that port will be forwarding to my internal ip assigned at the time.
Sure I would still have to use some DDNS service.
Sure I would still have to use some DDNS service.