Do you think it a significant detail in the story that Anil is a struggling writer? Does this explain his behaviour in my way?

Yes, it can be inferred clearly from the story that Anil was a struggling writer. Initially, he refused to keep Hari as he couldn’t pay him. However, his good nature made him pity on Hari Singh who didn’t have any work to do. He agreed to keep Hari but offered only food. It is also mentioned in the story that he made money by fits and starts but he wasn’t a miser which can be inferred from the concluding part of the story in which he told Hari that he would then be paid regularly (since Anil had received some money from a publisher).