[shultays]

Should "hello world" return error if it actually prints something but there was no person to read the output? Maybe the user was distracted and was not looking at the screen. Does a "hello world" program make sound if no one hears it?

Sounds like the program failed its objective, greeting the world. And thus imho shouldn't return 0.

[masklinn]

The program’s objective was to output the information, not to ensure that a user read it. Redirecting to `/dev/null` is a valid and common use of a program warranting no warning, so is running a program, collecting its log, then ultimately discarding it having never looked at it (in fact it’s the norm of well-behaved and solid programs).