As a Roblox developer, it is difficult not to make mistakes in selecting the right value for StarterGui.ScreenOrientation, because of the existence of LandscapeLeft and LandscapeRight. These options should never be picked by developers, because you risk giving players an upside-down experience and needing to have them turn their screen.
There is absolutely no reason for developers to ever want to pick LandscapeLeft or LandscapeRight. They are redundant because picking one or the other will upset a significant portion of the playerbase (I’m not sure if it’s exactly 50%/50% between the two, but it seems to be at least 75%/25% in how players normally are holding the device as the game starts).
Developers should always pick either Portrait, LandscapeSensor, or Sensor. There is no use case for wanting to fix the screen into either left or right orientation, considering that you are forcing part of your players to physically flip their device which is a really bad experience (consider someone with their tablet/phone plugged into power, and they can’t turn their device without the cable being too short, or they can’t easily reach for device buttons anymore after turning due to motor issues or device layout).
If Roblox would deprecate these two enumerator items and remove them from the ScreenOrientation dropdown, this would improve the mobile experience both for developers and for players, because developers will not be able to fall for this trap anymore and accidentally inconvenience their mobile players.