As a developer I would like to have a delayed hiding of loading screen. Turning off a loading screen immediately might become problematic in cases when more components are trying to show or hide the loading screen by itself.
For instance, in eZ Studio the PlatformUI handles hiding of loading screen by itself, what is problematic, because of preview not being fully loaded while the view itself is already rendered and ready to use. In that case, the loading screen should not be hidden.