What we build and what we engineer has very little to do with engineering itself… and building a “good” solution in the real world – that is, outside of an academic or theoretic context – is largely measured on how well it is received and used by its intended audience.
Books are a wonderful example here, actually – there are two predominant directions a serious author may take his or her writing: either a.) literary acclaim within the field, or b.) popularity on the market. These two types of literature are almost never seen in one book, as one is exquisitely written and unfolds like a piece of art, while the other? Simply amuses; delights; entertains. And typically reads quickly, straightforwardly, with little left to interpretation. People love that.
Most things are this way. We know of particular buildings which are celebrated and revered in the architecture world and yet stand mostly vacant, abandoned or avoided by potential tenants. There are pieces of fashion never meant to be worn beyond the runway; never meant for consumption by “real” people. And yes, in technology, there is a way to build to showcase engineering capabilities or, conversely, a way to design to please the person on the other end.
“Cooler” does not necessarily mean “good” – not beyond those in the industry, anyway, who are the majority of people who can appreciate and understand the “coolness.”
“Good,” in my mind, is measured by how much your product is used by its intended user. (In fact, not just used, but cherished.)
And, in my mind, the value and meaning of a rich emotional response holds true regardless of product, whether book, building, garment, or app. This is the real depth of design: to delight the user; to give them something that makes their lives just that much better.