If we believe the vision for Apple expressed by Steve Jobs, it's all about technology leading to the experience.
They are foremost about a cohesive experience that is enabled by technology. That would mean that the primary purpose of the non-removable battery in Apple's gadgets is not to annoy you, or to deliver additional revenues to Apple stores. The purpose would be experience, right?
Well, that is what an Apple patent filing that describes an "integrated embedded battery" appears to outline as well. The patent claim simply explains "a plurality of battery cells, wherein each battery cell is directly attached to a housing for enclosing operational components of the portable computing device, […] wherein the protective structure is configured to protect the battery cell from a compressive force applied to the housing of the portable computing device, the protective structure being attached to or integral with the housing and having a height greater than that of each of the battery cells."
However, the background description of the filed patent is much more revealing. In fact, the reasoning behind Apple's embedded battery is a great example of Apple's thinking behind the design of its products. Apple explains that the design of compact portable computing devices means that there can be "complex tradeoffs" and notes that the battery may be such a tradeoff. The design of the device can affect the battery in its general type, its energy density, durability and packaging.
As a result, Apple says that its embedded battery is a solution for a "portable computing device that is durable, lightweight and efficiently packaged." The description of this specific embedded battery shows an extraordinary amount of attention to the goal of supporting the design of the device as experiences by the user. For example, there are structural "ribs' that protect the battery from compression, but are lighter than a structure that would need to be present were the battery removable.
For replacement purposes, the battery was designed - even if consumers cannot replace the battery themselves, for easy removal: "As the battery cells are not enclosed in a separate pack, they are therefore easily accessible. Thus, the lack of a separate pack makes it easier to identify and repair or replace faulty battery cell. A removal mechanism, such as a pull tab or a removal handle, can be attached to the battery cell to facilitate removal of a battery cell that needs to be repaired or replaced."