What also interesting is that only beaked bird lineages survived the KT extinction. Perhaps their ability to eat stored seeds and nuts contributed. However afterward, without the competition from pterosaurs, birds filled specialized meat eating niches once again. Teeth would become useful again. This time evolution experimented with 'pseudoteeth' rather than reactivating latent tooth genes. These birds had bony toothlike protrusions from the jaw that were covered with keratin. Pelagornithidae - Wikipedia
Evolution doesn't always take the most logical route but given enough time and repetitions it arrives at useful adaptations.