The splash screen or launcher image is there to give the user immediate feedback that the app has started and is loading. Both Google and Apple has it in their guidelines that the splash image is there to improve the UX by simulating faster loading times. Not by advertising your brand.
Supply a plain launch image that improves the user experience. In particular, the launch image isn’t an opportunity to provide:
An “app entry experience,” such as a splash screen
An About window
Branding elements, unless they are a static part of your app’s first screen
Instead, give the user a sense of that the app is quick when loading data.
Design a launch image that is identical to the first screen of the app, except for:
Text. The launch image is static, so any text you display in it won’t be localized.
UI elements that might change. If you include elements that might look different when the app finishes launching, users can experience an unpleasant flash between the launch image and the first app screen.
If your application has a time-consuming initial setup phase, consider showing a splash screen or rendering the main view as quickly as possible, indicate that loading is in progress and fill the information asynchronously. In either case, you should indicate somehow that progress is being made, lest the user perceive that the application is frozen.
From my perspective, the brand identity is the only reason to show anything except an empty version of the first screen of the app. For me as a user that already knows what app I'm opening, it doesn't provide anything. What I want to know is that the app is loading so that I can start using it.