For example someone might say:
The light of the moon is shining brightly tonight.
And a physicist might respond:
Actually the moon is not a source of light, it is reflecting light emitted by the sun.
Whether that response is pedantic, helpful, playful, annoying or whatever probably depends on a complex set contextual considerations. But whatever the intent or reception, it is nevertheless a meaningful distinction that is being made.
Is it your opinion then that since the moon's light is derived that the earths shape could also turn out to be illusory?