Yes, it's fine. Your student is using personification. See the 3rd definition here darling definition | Dictionary.com
3. a person or thing in great favor; a favorite: She was the darling of café society.
Last week I asked my students to write about the merits and demerits of ebooks and physical books telling about their personal preferences. One of my students came up with this title for her composition: E-book--Darling of the 21st Century. I doubted the use of "darling" in this title, so I went to my Oxford dictionary and got the following explanation: The darling of somebody or something is a person who is especially liked and very popular. Here's a contradiction: ebook is not a person. Do you think "darling" can be used in this figurative way to draw attention from the reader?
It was a pity that I didn't get any clue concerning this issue when I went googling before coming here.
It seems ironic that I, as a teacher, often come across things in my students' compositions that I'm not sure of.
Thanks for the link.
I agree it's an excellent title.