Confirming March reports that Microsoft would make a Cortana app for iOS and Android, Microsoft announced today that a Cortana app will ship for Android in late June and for iOS later in the year.

Windows 10 will come with an app called the Phone Companion that's designed to help Windows 10 work better with smartphones. Plug an iOS or Android handset into a Windows 10 machine and the Phone Companion will help install Microsoft's range of phone apps onto the device. Office, OneNote, OneDrive, Skype, and Outlook are all out now and will soon be joined by Cortana and Music. This app should be available in a new Insider Preview of Windows 10 that will ship in the next few weeks.

The purpose is to ensure that Microsoft's set of synchronized services are always available; if you have a picture or song or document on your PC, it should be available and usable on your phone, too, and vice versa. As part of this, certain features that are currently Windows-only—such as Music's support for playing music from OneDrive—will be added to the iOS and Android apps.

And it also means that Microsoft's Cortana digital assistant will be made available for those platforms. Microsoft says that the experience will be comparable to the one in Windows and Windows Phone, but not identical. While things like questions, alerts (including geographic ones) and flight tracking will all work, Cortana on iOS and Android won't be able to launch apps, change system settings, or respond to the always-available hands-free "Hey Cortana" trigger that's available in Windows 10 and on some Windows Phones.

Similarly, Microsoft's Edge browser with its Cortana integration will remain Windows-only, as Redmond has no intention of making the browser cross-platform.

The spread of Cortana, along with Microsoft's attempt to promote its mobile apps, is consistent with the position that Microsoft CEO Satya Nadella has laid out a number of times: the focus is not on mobility of devices per se, but on the mobility of experiences across devices. People will continue to use a mix of gadgets—a phone, a PC, sometimes a games console or a tablet, and one day even a holographic headset—and Microsoft is trying to make sure that whatever device they happen to be using, they will still have access to Microsoft's software and services.

Use Windows on your phone or tablet, and you'll have in some ways the best realization of this ambition: services like OneDrive and Music will be installed and set up automatically. Stick to the Windows family and you'll also get mobility of third-party apps, as the Universal Windows Platform makes it possible for developers to write software that spans the full range of device types and form factors.

But even with a Windows PC and an Apple or Android phone, you'll still get Microsoft's set of services wherever you go. Nonetheless, the value and utility feels a little hard to divine. While having more users will help aspects of Cortana—more users talking to her should improve the quality of speech recognition—it does little to help sell any of Microsoft's software or services.

It's not even obvious why iOS or Android users would care about Cortana when they have Siri and Google Now instead. Those competing digital assistants will be easier to access and will offer richer platform integration and greater capabilities. They're likely to always be the preferred choice of non-Windows users. As such, our opinion is much the same as it was in March: offering Cortana on iOS and Android means one less reason to care about Windows, while providing little incentive to care about Microsoft's paid services.