Summary: It only works with iPhones, so it’s useless to me.

Note that it doesn’t only work with iOS devices, it’s specifically limited to the iPhone; compatibility is articifically limited from both iPads and iPods.

The latest (among several) revisions of either the iPad Pro, iPad Air, iPad Mini, and iPod Touch all meet every possible requirement for the Apple Watch (as established by the minimum supported iPhone 5), the only thing they lack compared to an iPhone are cellular connectivity.

Cellular connectivity affects how likely you are at any given time to have a data connection. However, presence of data connectivity is a purely quantitative measure, an iPod user in an area with wifi coverage will trivially have better data connectivity than an iPhone user in an area with neither wifi nor cellular coverage.

Pretty clear case of Apple using artificial software limitations to place business needs (selling more iPhones) ahead of user needs (non-Iphone iPod/iPad users using Apple Watch.)

I only mentioned cellular data rather than voice/sms ability, because the situation seems especially ironic when discussing those - due to iMessage and FaceTime over either wifi or cellular data, voice/sms is nearly irrelevant to an iOS user unless he or she needs voice/sms for communication with non-iOS users… who are exactly the users who aren’t being catered to with Apple Watch.