I appreciate your point, but I still believe spelled-out numbers work better.

In prose, especially fiction writing, the ideal case is that the words themselves slide neatly out of the way and become invisible, leaving only a picture in the reader's mind. Generally speaking, anything distracting is therefore counter-productive for fiction. Strange fonts and strange typesetting, while interesting, take the reader out of the prose. There's a reason almost every fiction book you pick up from the shelf uses Garamond.

In an engineering context, remembering exactly "12 eggs, 6 toast" is probably the most important thing, and numeric digits assist in that. In fiction however it doesn't matter if, by the next page, the reader has forgotten exactly how many eggs there were; the important aspect is to convey the sense of a large and chaotic family, and the overall impression is more important than the detail.

Thats why although the numbers are important for setting the scene, we really don't want them to jump out and steal attention. We don't want anything at all to have undue prominence, because the reader needs to process the paragraph as a cohesive whole, and see the scene, not the specific numbers.