Killer apps can lead to great broad success.

For AR, I can imagine that sticky notes could be of great use.

For example, you notice that cold air is entering your home through a gap in the window frame. You can make an AR note at that very spot, and next time you look at it, you will be reminded.

Even better, attach notes to people. Like their names. Or something you shouldn’t mention. If that note is in your face when looking at them, you should be OK