The sarcastic answer is that there IS NO POINT of a gallbladder in that you will be just fine if you get your gallbladder removed. However, the gallbladder would not be part of the human body if it didn't have an original purpose, even if that purpose only has to do with human evolution (as is the case in regards to the appendix).
The image in the above answer is a good one to show the "point" of the gallbladder, which is a tiny little organ near the liver. You can learn a lot about the "point" of the gallbladder if you split the word up into its roots: "gall" and "bladder." The general definition of a bladder is something that holds something else. In this case, this bladder holds gall. Gall is simply nasty juice called "bile" (made in the liver) that helps digest fat. The bile is eventually let out of the "bile duct" in order to continue the process.
I can also end with a personal anecdote in that many of my family members have gallstones. If one of those little things blocks the bile duct in the gallbladder, it will have to be removed. Why? Intense pain! And the irony is that some people can have a gallbladder FULL of stones, but never have the duct be blocked and feel just fine. I can see why you got to the stage of asking "what is the point." But simply, it is this: the point of the gallbladder is to store bile in order to digest fat.