Personally I think they’ve shown plenty of compelling use cases.
1) Utilize an effectively infinite number of floating displays, running multiple full-sized iOS and MacOS apps/games which are endlessly resizable and repositionable, in any room or while traveling.
2) Set up a standing/walking workspace that's not about rising desks or treadmills, but simply utilizing your whole space
3) View 3D assets (design prototypes, architecture, products, video game characters) in your space
4) Watch 180 Immersive Videos and 3D films in a virtual cinema, without 3D glasses that reduce clarity and brightness
5) Enjoy your photo library with 6-foot tall photos, wraparound panoramas, or 3D spatial home videos
6) Listen to Spatial Audio without headphones or earbuds
7) Replace your physical environment with a photorealistic nature environment to increase calm and focus
8) Rehearse a presentation in a virtual conference room or auditorium
9) Interact with your digital content without using controllers or physical input, e.g. while your hands are dirty cooking or doing repairs
10) Capture first-person, hands-free spatial video
11) View video conferencing participants life-size, with spatially-separated audio that makes it easier to parse crosstalk
12) Collaborate remotely, with participants' face and hands being present 3D in each other's spaces and thus able to gesticulate and reference digital content like you're physically together with a whiteboard
13) Adjust the lighting in your room, e.g. darken to focus on an image or presentation deck, or add more sunlight to improve your mood.
14) For the handicapped or others with mobility issues, control a computer with just your eyes