"Roughening up the soil" is a rather odd term for a gardening book. Assuming that the author means surface tilling, then he or she is probably incorrect. The opposite of surface tilling is conservation tillage, which allows at least some plant residue to remain on top of the soil over the winter. It is usually used to help prevent water and wind erosion, and, according to the 5th Edition of Soil Science and Management by Edward Plaster (c. 2009):
...conservation tillage increases soil moisture by improving infiltration and reducing runoff, reducing evaporation, and trapping snow [in the plant residue]... Conservation tillage also increases biological diversity in the field... this means more diverse soil microflora, more diverse insect populationns, as well as higher numbers of earthworms.
So, the opposite effect listed in your gardening book. Unless your caked soil also contains vegetable/plant residue, it is not an example of conservation tillage and actually prevents water from soaking into the soil, increasing runoff and erosion.
Now not all agricultural practices apply to home gardens, but this is as close as I could find to answer your question.
A better way to increase soil moisture content and prevent evaporation and erosion is an application of compost to increase the organic content of the soil and/or an application of at least an inch-thick layer of arborist wood chips as a mulch. With a mulch you won't ever need to till or "rough up" your soil again.