This is referred to as “standalone” mode, and it explains why, every time you tap on a shortcut icon from the home screen, you see a splash screen for a second before the associated action is launched ...

While the use cases for this icon creation tool are vast ... Home screen launch directly into the Shortcuts app rather than showing a white screen first as part of their web clip implementation. More ...

The Pixel Launcher is preparing to let you customize the shapes of home screen icons, and we have an early look at this new feature.