Being heavily involved in the fan art genre, there's a few words I have to say about it. Fan art is pretty straight forward to understand it's purpose, but I think there is more depth to it than a mere cheap drawing of a character from a certain IP. From what I've seen 'til now, there are mainly two motives that drive an artist to create fan art: for self expression or for its reward.
Creating fan art for self expression is when the artist experienced one or multiple moments in an IP that made them feel a strong connection/attachment to said IP, and have the urge to translate that experience in their art. When an artist have a strong passion about a certain subject matter, more often than not an evocative, creative, and stunning works will follow. When that passion is communicated in this fashion to others who share the same love for a series, it's definitely one of the most enriching experiences out there for the audience as well as the creator. This is why hundreds of thousands of people gather at anime conventions world wide, and this is the very reason why manga, anime, movies, books, paintings, or any type of art out there are made. Fan art can be just as powerful as any other types of art out there.
When I say creating fan art for the reward, I mean when the artist has little to no experience with the IP they are drawing and is solely after the publicity and/or profit that they may gain from drawing said IP. For example, an artist draws a character from the mega hit anime/manga series One Piece because they see potential in gaining more followers on SNS by doing so, but doesn't particularly like the series and/or just straight up didn't read it. It's not like there's a moral problem here; anyone can draw anything they want whether it'd be for publicty, for money, or anything it doesn't matter those are all good things. But in this case it's fundamentally incorrect to even consider this fan art, because said artist is not a fan and there is no communication relevant to the subject matter with their work. So then what is left of their work I have to wonder? It's like writing a review of a movie without watching the movie; absolute nonsense.
I think art is essentially communication, whether it'd be self expression, a reaction, commercial purpose, etc. A fan art is a communication of a certain experience, be that a character's personality, something they said, a point of their development, a meaningful scene, etc. and I think fan artists should have more self respect for their own works than just doing it to gain more SNS followers.
Sorry for the poor language skills I'm not a writer haha I just felt like ranting 'cause it's a topic that's on my mind all the time.