Dubious marine biology in Disney's The Little Mermaid

Back when I was four years old, Disney had just  come out with a new movie called The Little Mermaid. I had never heard of the much older, and even more bizarre, story by Hans Christian Andersen. Anyway, the movie has been a pretty big hit over the years and I'm just going to assume you've seen it. Like many Disney productions back then this version of The Little Mermaid is a musical. The title mermaid, Ariel, sings a famous song called "Part of Your World" in which she expresses her longing to experience the wonders of the terrestrial life. This piece takes place in a cave filled with her collection of human artifacts that are presumably either from shipwrecks, acquired from coastal settlements by her legion of marauding waterfowl, or some combination of those two things (I don't recall the extent to which the movie addresses this). This song contains the line, "Up where they stay all day in the sun." Now, for the purposes of storytelling, I can suspend my disbelief that mermaids exist and that this particular mermaid is obsessed with humans and wants to be one, but I cannot suspend my disbelief that a mermaid, clearly a pelagic creature as depicted in this movie, would have the terrestrial notion of deriving pleasure from extended exposure to direct sunlight. While she can and does surface, she is shown spending most of her time near the seafloor along what is presumably a continental shelf, in water that is deep enough to scatter a lot of the sunlight. She could hang out on or near the surface all day if she wanted to, and evidently visits often enough to be acquainted with local waterfowl (potential agents for her acquisition of human artifacts), but she doesn't spend "all day" in the sun. Fascination with subjects alien to her such as walking on streets, jumping, dancing, running, and fire is, perhaps, plausible. But she already has experience with direct sunlight and doesn't spend all day in it. There's no reason it would hold any mystique for her.