Whats the consensus on this trait when considering what an Incorporeal creature/character can and can't do?

Incorporeal critters can be hurt by anything "magicky", but can their magicky stuff hurt non-incorporeal stuff?

The trait is incredibly vague on what it considers an appropriate talent or trait for affecting physical things, does psychic powers work or warp weapons?

I know it can be incredibly imbalanced if they can affect the physical, in the case of Flicker for example... But by the same token Aegis of Euphadros would be an incredibly pointless power if it did not allow the psyker to blast away physical stuff with his/her powers.

Incorporeal stuff cannot usually affect the mortal world in any way, shape or form as per the trait description. However in some cases they can be affected by the mortal world like force weapons, psychic powers and possibly some potent relic/daemonic weaponry.

The appropriate trait it may be referring to is something from the next page like "Phase", to allow it to pass into our reality for a moment to strike. Or perhaps the ability to unleash certain psychic powers, the essence of the warp cares not for dimensional instability. That or you may give it a custom special ability etc.