I discovered RAW a few months ago, and wish I knew about it earlier.
I use Lightroom for all my photo editing now, I haven't had any reasons to head back in to Photoshop to fix up or change anything.
So now, Photoshop is now a work tool, and Lightroom for fun
RAW saves all the information the camera captured, where as a JPG is a flat image.
Think of RAW like the raw ingredients going in to cooking, they're sitting there unprocessed and not quite ready to consume. You cook them (edit in Lightroom), and export them in to a JPG for consumption. You can still add things to the final product to make it how you like, but that's it.
If you over cook a JPG from the camera then that's it, you're stuck with that, and can't fix it up too much. (depending on how bad)
If you under cook a JPG you might be able to recover a bit more, but again that's a stretch.
But with RAW you can always go back and change it again, and again, and again!
I used to always shoot in JPG and edit in Photoshop, I made do just fine. But there was always something my fussy self would notice but I'd make do. Now that it comes to RAW, I'm so much happier with the final products!