Camera lenses can suffer from a variety of lens defects. Fortunately, most of these can be suppressed somewhat via computer edits. And this kind of post-processing becomes a lot easier when you shoot RAW.
Almost every photographer’s artistic development goes like this: first they take a camera and photograph everything without being aware that there are any rules, and so they break them with a clean conscience (and unconsciously). Then they dive into studying photography, start applying and following its rules, and finally reach the point where they once again start breaking them—but this time knowledgeably, and on purpose.