It's a little complicated to tell you everything about using layers. But essentially you're right. Using them gives you lots of flexibility.
You also have blend modes that will have the layers interact very differently when you switch one on and off.
Others will doubtless tell you a lot, but I would say to look in the "Tips and Tricks" section of the Forums. And also rush over to YouTube. A number of people who have posted here have done video tutorials that were posted there.
The fact about using them is you don't have to know absolutely everything about layers to use them perfectly for the functions you want. Just learn as you need otherwise like anything in learning computers, the complexity can be daunting. I usually have it down to a select few functions using layers and that's enough for my needs, mostly.
Have fun. Play around and see what Layers do.
"Not a bit is wasted and the best is yet to come. . ." -- remembered from a dream