I'm not sure. The most obvious possibilities to me are:
1. Someone has a win con requiring a null.
2. It's just flavor text, though I'd be disappointed.
3. It interacts with ice-cream flavors in some regard
4. Someone has a win-con requiring no nulls.
5. Actually, there are no scum if we lynch null! Everyone wins, everyone gets ice-cream. (Oh wait, that last one already happened.)
Ultimately, it's something of a question of the GM's psychology. What kind of mechanic would IJW introduce after commentary and revision. I don't know well enough to make any strong guesses, particularly as this is only my second game.
What I would like to see is to use these mechanics as levers, in contrast to other set-ups where they're not useful tools. As I understand it, a lot of
@Nictis's opposition to voting null D1 is that it's not really a productive argument, particularly early in the day. By contrast, here the mechanics do invoke lynching null. It is something that might generate a response beyond just an (apparently) rehashed argument. Making the unknowns a topic of conversation is the only easy way to see if they're less unknown to anyone else. Even if no one has the picture themselves, it's only by discussion that we can really figure out what it might look like.