I don't think we're necessarily disagreeing. I'm not saying technical details are going to make a sale (almost ever), but if one of the members of the sales team (note that I'm classifying the "sales engineer" as a salesman) can grant credibility & real world experience to the lofty promises that the typical salesman makes, it adds a level of differentiation that can—in some instances—make or break a sale.

Also, to clarify, it also really depends on the nature of the industry, the product, and even what we're considering technical details.