These are useful for much more than just "debugging" - using any commands, getting exact durability value, learning English, etc. Plus, this toggle is not visible in vanilla options so many people may not even know about it.
Makes the splash screen black and white
Black background is less intrusive than red, partial Bedrock Edition parity
Size of the menu and interface elements
3 is more usable on most screens, 0 (Auto) can get too large on Full HD and larger screens
I expect my users to already know that Social Interactions can be opened with
P; the screen is easily discoverable by the "Player Reporting" button
260 means "unlimited", this is changed for better UX when VSync is disabled by the user (on fast computers/monitors)
Indicates whether the user has not seen the accessibility onboarding screen
Minecraft already has an easily accessible accessibility button in the main menu, this screen just creates annoyances for the majority who don't need it
Shows operator-only items in a Creative inventory tab, when you have operator access (
It is useful and it only appears when you have the permission for it, so it's weird Mojang even made it an option
Adjusts which resource packs are enabled by default
Adjusts the game's language
Enables user's system language by default, for usability, accessibility and discoverability purposes - courtesy of Language Reload. Not available for all launchers and operating systems.
Redstone and mob spawning distance
Better performance regardless of the rendering distance you use
I expect my users to already know that the third party servers are not owned or monitored by Mojang Studios or Microsoft.
Toggles Snooper, the legacy analytics service
Just in case you use the same profile on MC 1.13 or older, to improve privacy. The setting was removed in 1.13 but it still exists in options (and defaults to enabled) for some reason, hence the change.
Sets the telemetry (analytics data collection) toggle to "minimal".
While "minimal" is the default right now anyway, it may not always be the case, hence the enforcement by FO. Debugify is used to disable it entirely though, so this is also just a fallback.
If you know how to install a modpack, you probably don't need those tutorials anymore