Wouldn't sweeping the soil be the equivalent of tilling? Thought the farm industry was moving to no-till to prevent nutrient run off from water and wind. I know University of Iowa has done a number of studies that show tilling is long-term harmful to the soil composition.
Not at all. It has nothing to do with tilling. We're just talking about mechanical weed control using a rotary hoe or a tine weeder. The job of a tine weeder is to pull out the weeds just as they sprout.
The downsides of tilling happen because you flip the soil at a depth of 25-35cm, which disturbs the micro and macro fauna, and builds a layer of crust that the roots have a hard time penetrating, especially if you till in wet conditions. The issues with erosion are more a result of prolonged exposure of uncovered soil to the elements. You're not going to do any of that in a raised garden bed.
*fixed typo