i'm gonna have to stop you right there.
prose may have the power of description but dialogue with it carries baggage and connotations. they may not be as long as prose but they can be just as significant. this might be discrepancies of tastes between readers but for me, a perfect, succinct line of dialogue is much more satisfying than a closing paragraph. case in point, take Lee Child's recurring Jack Reacher series. the whole series just revolves around the eponymous protagonist going across the states solving mysteries and avenging murders then leaving with no baggage or name or even settling down. he just comes in, does his shit, saves the day, and leaves; that's his entire appeal. every book ends with an epilogue showing Reacher hitchhiking after the climax. he just gets on a bus or a truck and leaves. in the early entries, Child would just write something akin to "he took a bus heading towards Anywhere, USA." in the later parts, however, he's added a bit of dialogue in the end, and to me, just brings more flavour than one block of text would have.
"Where you heading?"
"Where you stopping?"
"Las Vegas, you?"
"Somewhere in between."
one thing dialogue punches out more than prose is because; and I hate being a broken record; it reinforces the show don't tell theory. Jack Reacher is a wild card. he's a drifter that goes places with no goals or destinations in mind. trouble comes his way; he doesn't look out for it. a prose would just tell the readers that he's going somewhere and trouble is likely to follow. dialogue shows us that Reacher isn't finding trouble at all. he's as oriented as a windmill and wants nothing more than to be somewhere else. with the whole baggage that is the entire book sitting before the epilogue, the story didn't need an entire block of text to tell you about it. the reader has already read the book and understood contexts and subtlety. dialogue is there to sell them; to reward the readers for their attention and investment throughout the book.
of course, this is a different case for every book. some books fare better with an expositional end, while others could do better than a snippet of a conversation. in the case of Lord of the Flies, the closing paragraph sells the nightmare that the boys went through and the madness they've descended. i prefer dialogue than prose but in my honest opinion, I'm going for the yin yang approach. both is good. in various situations, one shines better than the other.
and to answer the thread's question, prose and dialogue is like beer and wine. one's cheap and one's expensive, but you wouldn't grab wine with the boys on a Saturday night or clink beer in a candle lit dinner.