Do agents really care if the novel is poorly written as long as the story is unique and interesting?

Obviously I'm not talking about submitting something illiterate, but not amazing. Think Twilight Saga and Fifty Shades of Grey. These books are mocked for being poorly written, but look at their success.
As long as the agent believes the book will be popular, does it matter if the writing isn't "breathtakingly beautiful and heartbreaking."

Do agents really care if the novel is poorly written as long as the story is unique and interesting?