Where it gets interesting is when a technology that’s designed for developer convenience is made out of the very materials being delivered to users. For example, a CSS framework like Bootstrap is made of CSS. That’s different to a tool like Sass which outputs CSS. Whether or not a developer chooses to use Sass is irrelevant to the user—the final output will be CSS either way. But if a developer chooses to use a CSS framework, that decision has a direct impact on the user experience. The user must download the framework in order for the developer to get the benefit.Source: Adactio: Journal—Split
This is exactly the kind of thing I have been thinking about with the growth of today's web development workflow. Jeremy Keith has such a great way of hitting the nail on the head when raising big issues in the web development world.