A little of this, a little of that.

Most folks use the term "entertainment" in this context to mean "distraction;" and by that to refer to literature which doesn't challenge the reader to interpret it.

The "genres" ( particularly Science Fiction and Fantasy ) are known for a less experimental approach to style. I recall an author pointing out that if your characters are beings with unconventional anatomy you ought not say "his eyes followed her down the street," casually.

Of course the distinctions are artificial, and only seem concrete because of Publishing conventions and ( to a lesser degree ) audience expectations. I've seen Jonathan Lethem filed almost everywhere possible; except maybe in children's picture books.

And, of course, those disparaging "genre fiction" tend to cite the classics of literary fiction, rather than rattling off this months offerings in that publishing category.

Classics have the advantage of having been culled from the dross over the centuries. So its hardly a fair comparison. And anyone whose been to a bookstore ( remember them ) recently will find a lot of lightweight reads among the "literary fiction" category. ( Is Jackie Collins undying prose? )

But then again, when someone wanders into that section for easy distraction, they tend to describe those novels as "trash" too, despite them not adhering to any particular genre.

Dante