One of the biggest advantages to the prime lens is the ability to allow you to photograph in dimmer light, in the house, store, museum etc. It is also going to be smaller and lighter.
You have the idea though, try these lenses & if it works for you pick up a normal 50/2 or the like & sell off one of the others. It will most likely pay for the normal lens.
Regarding the image quality, I've sold hundreds of cameras with "kit" lenses and only a small handful of times was anyone displeased, but most people don't have a very sophisticated eye.
Just for curiosity what country are you in?