I agree as the size of the app ecosystem is an important measure to take into account for both consumption and productive apps. If the utilization of these apps were below acceptable levels, then over time the app ecosystem would shrink because demand would not be enough to cover the cost of developing an app.
Initially, it is difficult for consumers to compare a product that is aiming for a new category. For instance, a segment of the population required smart phones with larger screen and tablets with small screen, hence, the hybrid phone/tablet or phonelet. In the same way, the Surface line is also an attempt to cater to a segment that exists between the PC and tablet world. However, this category has no name as yet.