Sorry, what I meant is that no one needs 5G but people would still sell it as if it's necessary, or a huge future. The features will be pumped with filler until they can expand to fit the feature space.
You could convince people that they do need to fling high resolution medical imaging from office to office without lag, and that 5G could make it happen. You tell them the IoT can become like skynet, and they'll sign up because they think it's going to make their lives more convenient. As an app developer, it becomes a buzzword that you can slap onto your shitty startup, e.g. "ONLY POSSIBLE WITH NEW 5G" or "INNOVATIVE, NEW TECHNOLOGY YOU'VE NEVER SEEN BEFORE!" Realistically, though, we'd either see a bloat in the type and amount of data being sent over mobile apps or no change at all, and the world wouldn't be any better for it.
Basically, the use case isn't technological: it's the ability to sell a higher number. Most people I know are willing to accept that this one goes to 11.