The appeal lies in its fresh take on the BL genre. The art style is great, and the character development is deep and relatable. Plus, it has some unexpected plot twists that keep you hooked.
I could be okay with BL sandwiches in manga if they are well-integrated and add something unique to the plot. But otherwise, I'd rather they weren't there.
One similar BL novel could be 'Given'. It has a great story about music and the relationship between the main characters that develops in a very heartwarming way.