You’ll need a Tradfri Gateway to use the shortcut button, and to connected devices (like smart lights or speakers), you’ll need the IKEA Home iOS or Android app. According to the user guide, shared as part of the FCC listing, the device should last two years before its battery needs to be replaced.
Teknikveckan suggests it might be possible to add different symbols to the button to show what scene it controls. The photo in the FCC filing shows the device with a bed and a moon on the front. Unfortunately, the leak did not include any hint of when IKEA might release the device or how much it will cost. Though, as The Verge points out, it will likely cost less than other smart home hubs.