Sure it is! I've heard of people who sculpt or paint as a hobby, and they do it because they're passionate about it. Last thing they want to do is make a business out of it because it'll kill their passion. It's all up to the individual writer. If the reason to write is to be published and entertain, then that's good. If the reason is just because it's a fun little hobby, then that's cool too. There's no right or wrong answer for this question.
