Does anyone know if there’s any hidden effect from giving Virginia the mask, such as allowing the story to continue at another place and time?
Not as far as I know. And I have feeling, that there shouldn’t be one - after all
she lost the mask to one of Mrs Plenty’s followers anyway. You can find it in cove once more with lore text specifically saying that
A big part of any Devil storyline, is that the Devils always play you for a fool. The narrative has been incredibly consistent in that: you will never get anything of worth out of them, only the promise of something delightful to come.
It is quite a feat on Failbetter’s behalf, that they keep them attractive even though they never deliver - but then again Faustus was quite the blueprint.