Apple has a grudge against physical buttons, especially the ones that take up too much space. The company has filed a patent that describes the design of a "compact pivoting input device", which will significantly reduce the internal volume that a button takes. It's not just space saving, though, this mechanism can offer programmable feedback. Such buttons can be provide different haptic feedback, configured by software, and will also be force-sensitive. The patent gives the iPhone power button as an example, so that's likely the first use case, but it these devices can find other uses...