The alternative would be capacitive buttons like the ones found on Android phones. The downside is that accidentally brushing against them could cause an unwanted action, but in a recent Apple patent (discovered by AppleInsider), it suggests a method in which the system could detect that the touch was unwanted and it would ignore it.
This could come in handy especially when our phones are in our pockets and where we might accidentally activate certain features. It is also possible that such a feature could be introduced to Apple’s rumored iWatch, especially since it is worn on the wrist and could be subject to accidental brushes against someone’s hand or arm.
In the patent, they gave an example of the iPod shuffle which can be worn via a clip. However in order to open the clip, you’d have to touch the device, so according to the patent, it will detect when this is being done and will keep the device inactive to prevent any unwanted actions being performed. It sounds like a good idea but given that it is a patent, there’s no telling if and when Apple will implement it. However we’ve seen the Cupertino company implement something similar with the iPad mini, where touches on the side of the device will not be registered as it knows you’re probably just holding the device.