Flat earthers are easily radicalised into right wing belief like "The world is controlled by Jewish lizards" and "the election was stolen from Trump" and "the vaccine contains a bill gates microchip that makes you gay". And right wing conspiracy theorists will willingly spend their life savings on Alex Jones dick engorgement supplements while generating culture war controversy to draw political attention away from actual issues like climate change and worker's rights that may harm big business interests.

Think of it this way: in the mediaeval age, you armed your peasants with shields and spears and had them protect your keep. In the information age, you arm your peasants with conspiracy theories and twitter accounts and have them protect your untaxed billions.