This episode wasn't as exciting as I'd hoped it would be, but the overall premise was what I expected: the gang spends most of the episode digging out Celesteela, and then Team Rocket interferes and tries to take Celesteela for their own. I assumed Team Rocket would learn Celesteela is an Ultra Beast and that would be their reason for wanting it, but instead, they were drawn to it because it's a rocket. Go figure.
I appreciate that
all of the Ultra Guardians were involved this time—especially the girls, who tend not to get as big a piece of the action as the boys. Lillie's idea for creating a barrier was pretty clever, and the girls made good use of their Ride Pokémon, as well as their partner Pokémon. In fact, during the scuffle with Team Rocket, the only one who wasn't doing anything
active was Sophocles. I expected Celesteela to be more dangerous for the Ultra Guardians to deal with, but even though they didn't actually battle it, it was still presented as a legitimate threat, because by launching, it would (unintentionally) burn down the bamboo grove. While that might not affect Ash and his friends (since they would be able to fly away), it would certainly affect Pokémon living in the area. Not to mention the overall damage the loss of the bamboo grove would be to the local ecosystem.
Was it really necessary for Celesteela to have been stuck in the ground for 200 years? I suppose it was an interesting way to tie it to the tale of Starship Kaguya, since it leaves open the question of whether the folk tale was inspired by Celesteela; but it also begs the question of how no one had discovered it and tried digging it out until Sophocles did.
I'm starting to suspect the Ultra Beasts will appear again in the future. Perhaps the Ultra Guardians end up going to Ultra Space themselves, where they encounter the Ultra Beasts again. It just seems rather odd that, aside from Nihilego, the Ultra Beasts have all been dealt with without a legitimate battle. Granted, we've only seen Buzzwole and Celesteela, but still...
Ash should've had a more important role in this episode though, his role was quite unimportant for a protagonist. Overall, 6/10.
Just because Ash is the protagonist doesn't mean he has to have the majority of the spotlight in every single major plot episode. Besides, he
did play a role in battling Team Rocket. This episode was more about Sophocles and his connection with Celesteela (even if that connection wasn't very strong).
Also, I really hope somebody other than Ash can catch an UB. Even if it's just for a small moment like Buzzwole, which would be most likely, it'd still be nice to see Kiawe, Mallow and the others.... maybe even the TRio in one episode... get that honor.
Don't forget Kiawe tried to catch Celesteela in thsi episode, so it's not as though Ash is the only one allowed to use Beast Balls. And don't get your hopes up for the TRio catching an Ultra Beast. I highly doubt that would happen.