If the line filter dies,  does it need to be replaced or can it be bypassed ????

Also I was told by a pinball tech that line filters were only a required for the us market and are not required on aussie pinballs, is this true ?

The machine will work perfectly without it BUT rando EFI (EMI) "Electromagnetic Interference" may affect other electronic items nearby (hence the USA requirement) or the Pinball machine might be affected by interference from external sources.

I would always fit one.