GP here. There are a few kinds of launch mechanisms in play here. It should be possible to open things that are based on links or files in a particular app as

GP here. There are a few kinds of launch mechanisms in play here. It should be possible to open things that are based on links or files in a particular app as a default. This is a good model because there’s already a Files app that allows a desktop file storage/manipulation method (same with files received over email or opened from a browser). Then you also have apps that are launched directly (without a file or URL as trigger). Couple of examples: you can swipe left on the lock screen to access the Apple camera app (or press the camera icon on the bottom right). Why shouldn’t this be as seamless to launch a better third party camera app (of which there are many)? As for calculator, the one launched from Control Center is always the Apple Calculator app. It’s not possible to launch another one as easily without adding it into the widgets area in the search screen (which may already be crowded). These two examples don’t require special hardware enablement (like the Apple Pay trigger required), and can improve the lives of many users.