Some people believe in all sorts of crazy shit.

How many of the people scoffing at these flat earth idiots believe in god, for instance?

My point being there is no value in holding a true (or false) belief if maintaining that belief does not mechanically impact one's life. But how one defines 'impact' can be squishy - even if a person does not require belief in a spherical earth (belief in a flat earth suffices) - having a belief in a spherical earth enriches one's appreciation of the planet or etc, and thus be a 'positive' belief.
However that opens up the question - If one holds a false belief that enriches one's appreciation or quality of life - is that a 'positive'. Is thast desireable? For example if I believed in angels, if I believed I had a guardian angel. Or if I received comfort believing that the dove outside my window was my dead grandmother visiting me.
An example of a positive false belief - if I believed and treated all firearms as if they were loaded - such a belief has better outcomes then if I believed and treated all firearms as if they are unloaded (as most are). For example, I am sitting around a table, someone picks up a pistol, confirms its unloaded, returns it to the table . . . person B picks up pistol, they will also confirm pistol is unloaded ,and so on . . . and no one will point that pistol at another individual even though all evidence confirms the pistol is not loaded.