There is lots of debate surrounding which is the best mobile platform, and despite the difficulties of switching between them users do switch platforms for a variety of reasons. According to Christian Cantrell, writing for Read Write, wearables are designed to lock users in to a given platform.
Defecting from one mobile faction to another may be inconvenient, but it’s not yet impossible, which is why major platform players are inclined to steer their devices and services in a direction that increases not only their allure, but also the cost of abandonment. And an important new weapon of mass disincentive is wearables.
Cantrell divides wearables into two camps. There are platforms-independent wearables, such as Fitbit, Jawbone, Pebble, Garmin, etc. These devices will work on more than one platform, and though the experience might not exactly the same it's close enough to be tolerable. Platform-dependant wearables are ones that... well... work on one platform. Both the Apple Watch and Android Wear are prime examples, as neither will work without a corresponding iPhone or Android phone, respectively.
However, if Google ports Android Wear to iOS (as is rumoured) it's possible we will have a third category. A platform-preferred wearable, which is a device that will work across platforms but offers more functionality on one of them.
The problem with the prospect of pairing an Android Wear smartwatch with an iPhone is that—due to constraints that limit deep third-party OS integration, or simply fundamental discrepancies in platform features—you are likely to find yourself in a kind of purgatory where your experience is worse than if you were using an Android phone, and also not as good as if you were wearing an Apple Watch. Many iPhone users who try to use Google services exclusively are already familiar with this unfortunate dynamic.
Cantrell notes that things like doing payments probably won't work across different devices and platforms. Both Apple Pay and Android Pay require the wearable to be tied to it's preferred platform. This limiting experience isn't a deal breaker for those who are embedded one or another ecosystem, but it's bad for people who want a diversity of experiences.
While keeping wearables tied to a specific platform, it makes a lot of sense from the company's perspective. Apple only has about 18% of the global smartphone market, yet it makes the over 90% of the industry profits. Platform retention is profitable for companies like Apple, even more so than shipping more Apple Watches by making it cross-platform compatible. Predictable revenue is important to the company's stakeholders, and pursuing a strategy that continues this legacy is important.
The author concludes by saying that wearables are a double edged sword.
In exchange for freeing ourselves from one burden, we are agreeing to take on another. That doesn’t mean we shouldn’t buy devices like smartwatches; it just means we should be fully aware of the fact that, as much as we’re strapping devices to ourselves, we are also strapping ourselves to our devices.