Dont beat your self up, it can be confusing at first but it will all come together and we are all here to help you out.
Typically people wont use a drip tip on an Ego-c because the atomizer is designed for the cart, which is more or less small tank. People will drip their juice directly onto the atty for better flavor, vapor, and/or throat hit. If that was something you were interested in trying you would want a regular 510 atomizer which would work on your current battery because it utilizes the same battery connection.
People will also drip on atomizers (atty) when trying new flavors because, not only do you taste the flavor better, but attys are much easier to clean when going from flavor to flavor. Drip Tips originally came about so you could just drip the juice through the tip as opposed to having to take it off everytime you needed to add a few drops of juice.
There are alot out there and some of them are very cool looking, and in a way make your PV a little more personalized. I will use them for cartomizers for the reasons I stated in my last post. I hope this clears it up for ya!! If you have any more questions just hit us up, we are here to help, and there is no such thing as a dumb question.