In the interview the founder says that the next step would be to investigate how the health of the crows is impacted from picking cigarette butts. Such negative effect should then be weighed against any positive health effect that could be achieved by adding extra nutrients to the "reward food". Malnutrition can be a problem for crows eating too much junk food (from garbage).
Man it's really coming home to me now. We're training animals to pick up the toxic remains of the toxic drugs that we produce because we just can't be bothered, and now we want to make sure they stay relatively healthy doing it.
We’re employing crows with health benefits.
Generally, animals don't eat things that aren't food. They have taste buds and olfactory senses, just like us, and eat things that taste and smell evolutionarily "good". For me, cigarettes smell bad and taste terrible (I tasted one when I was about 7), and I doubt it's much different for birds that are omnivores. I suppose one possible path to them actually eating cigarettes would be if some was accidentally ingested, then they became addicted.