I was watching yesterday, and got a new theory.

If the events of Voyage Home had never happened, there never would've been Cetacean Ops in 24th century starships.

My theory goes that when George and Gracie were brought to the 23rd century and saved Earth from the whale probe, humans realized that cetaceans were more intelligent than we'd previously thought.

Maybe Uhura and Dr. Taylor worked together to get the universal translator to work on whale and dolphin languages, and because of Scotty's clever modifications to the Klingon Bird of Prey they'd borrowed, they were able to start fitting Federation ships with similar tanks so that cetaceans could start joining Starfleet and serving on starships.

Without those events, Leiutenants Kimolu and Matt never would've gotten the opportunity to serve aboard the Cerritos.