If you do not need to use no one is forcing you to use it. I use Photoshop not Photoshop Elements. I do not install Lightroon so I do not even have the option to use its Library system and I only use Adobe Bridge. To batch some things and also do some meta data editing. Develop the work flow that works best for you.
When you say you use Photoshop, do you mean you use Photoshop Elements? These are two separate applications, and we can move your post. AFAIK, you don't need to you the Organizer in Elements, but the folks there can clarify.
I know nothing about Macs. In Windows, there is no way to uninstall the Organizer by itself. I assume it is the same way in Macs. You can probably delete the program files manually but I would be very careful doing that if I were you. There are a number of dependencies between the programs and you may get some unintended consequences. And if you are so concerned about 2.4 GB of storage space on your computer, I think you have bigger issues than the Organizer.