Back in August, much buzz arose about a new iOS 6 feature. WiFi plus Cellular promised to allow apps having trouble with WiFi to connect using cellular data. This option promised to allow devices to tap into their data plan upon encountering shaky WiFi connections.
As Megan Lavey-Heaton wrote this Summer,
This scenario can occur you've made a WiFi connection and it turns out to be pretty bad. The connection to the router is solid, but the Internet itself is pretty horrid -- case in point, most hotel rooms I've stayed in the past couple of years. Benjamin cites cases where you're making the transition between a place with WiFi, such as your home or a coffee shop, and places without. There's a middle ground where you're barely hanging onto a WiFi connection.
Fast forward to the Autumn, and iOS 6's release. For anyone installing iOS 6, and navigating to Settings > General > Cellular, you would have seen this instead. The options go directly from "Personal Hotspot" to "Use Cellular Data for".
This is a disappointment for many users, who we think would have welcomed a flexible approach to flaky WiFi connections. If you're a developer who installed the initial GM, you've probably lucked out. The final dev release's Cellular settings screen looks like this.