Right now there does seem to be an accidental reward for participating even if the murder isn't solved, which is that you get to loot the bodies rip.

i fucking spit out my drink i hate how right this is

also yeah tbh re: it's okay if murders go unsolved, i think what's more important is that there's a satisfying conclusion to either ending... something something "if you get away with it for at least x months then you get your murder reward" so the murderer doesn't have to keep it a secret forever and can eventually share with everyone what the solution was, i think that part's fun too even if the mystery goes unsolved IC. gestures at Komaeda.