Repetition is a necessary part of learning vocabulary and constructs in a foreign language. Just think of a song you like and part of it will likely play in your head. When language elements are accompanied by a catchy tune, there is a higher chance you will emotionally engage with them and crucially, remember them.
Since the goal of learning the building blocks of a language is being able to actually construct sentences, seeing them in context is important. A song is essentially a short story, with some parts narrated to us more than once, making them all the more memorable. Furthermore, you are likely to find useful words and phrases in songs that you wouldn’t ordinarily learn in a language class, for example.
An artist is a real-life ambassador for a culture and language, bringing personality to the learning experience. You get to grips with accents and uses of vocabulary in different regions, and perhaps you’ll become a fan of a musician that you otherwise may not have discovered.