Function over form. This is an argument I hear regularly, and there are a few variants: "It doesn't need to look good it needs to work" and so on. Is this true? Well... yes and no. The key attribute for any tool should be it's suitability for purpose however anything that has been designed to do a job, in order to do that job well, needs to have been well designed. Doing a job well, at least for humans, involves taking responsibility and pride in your work. For a designer this means setting loose a product which they have invested significant time and passion in and if the job has been done well it is evident not only in function but also in aesthetics.
The right materials, quality of construction, ergonomics and even artistic aesthetics all contribute to the hard-to-define appeal of a thing. A tool that presents excellence in these aspects shows a design investment that should translate comparatively into it's function and suitability for purpose.
Aesthetics is one of our most critical senses for the judgement of quality. We make these same assessments for the functional quality of genes in an attractive prospective mate or what food is safe to eat. We all believe that we can immediately judge the craftsmanship of furniture by the sturdy and elegant appearance of it's form and it's solid feel as we touch it. These same analyses should be applied to all of our choices from chocolate cake to word processors.
Form and function are two halves of the same whole and sacrificing either one will lead to poorer decisions. Aesthetics are an important factor for helping us make an informed decision by steering our judgement of the investment of effort, skill and enthusiasm in the creation of a thing. We all know that we perform better when we are passionate about something. When this is evident in the objects we use every day we can have more confidence in those things.