Both RAW and JPEG map pixels directly. The resolution doesn't change between them. The rest of what you wrote is true though.
Photoshop requires the Adobe CamerRAW plugin downloadable from the Adobe website for many versions of photoshop. If you have a very new camera you may need a very new ACR plugin which may mean you need the latest photoshop. Anyway try find the latest ACR that works for your version of photoshop and you will probably be all good.
RAW pics are better for editing since the JPEG is only 8bit, whereas RAW has the bit-depth of the sensor. This extra data makes the image look no different, however it is very welcome if you start editing since it takes much of the estimation and guesswork out of image editing algorithms. Editing should always be done in the highest bitdepth possible.
Ultimately that IS the big deal. You want to pull the best out of your camera then RAW is where it's at. With JPEG you're limited to what the camera manufacturer thinks your images should look like. With RAW you can customise everything about the conversion from the sensor to the image with far less quality loss, things such as white balance, colour profiles, tone curves, the works.
Also don't be surprised if the Adobe CameraRAW files look different in tone and colour to the camera JPEGs. Each manufacturer has their own idea of what "accurate" colour is, and in Adobe's case the AdobeStandard profile tries to match all cameras to one generic looking state. Some people like it specifically for that reason, some people hate it. If you are after the same colour and tonal reproduction as your JPEGs then you can either play around with the RAW settings, or use the camera's software like Nikon CaptureNX.