So rather than it being a "power of love thing", where if they love him (or he loves them, or both) the orb powers up and saves him, this is a purely physical thing?
Basically "if lips connect in a smooch, then orb powers up and saves him" thing, meaning rather than giving each girl this future dream, everything would be solved faster if she just made them kiss him instantly (while they are asleep in the future dream to avoid drama). Though I suppose him not having a body at the current time could make that problematic, so maybe that is why the dream is needed? But then she would just need to show them a dream of directly after he is saved, and make the lips touch while all of them are unconscious.
TL;DR - this seems to be a huge metaphor for the readers that would dislike the series if their girl doesn't win, and the orb is the money gained by pandering to every reader and writing an ending for each ship (where the kiss signifies "this girl won" like the trope that is is). So each ship that gets written is more money, and once all ships has been milked to their limit so orb is "filled up", the final harem ending will be made for those that like that.