Anyway, it's easy to look down upon Crystal if you disregard the Mobile Adapter. Even though only a minority of Japanese players enjoyed these features, Crystal created the foundation for the GTS (PCC back then), online distributions (Odd Egg and GS Ball) and Battle Recorder. It even had a News Machine that fostered a community feeling in Japan (by way of player rankings) as well as accommodating text-based mini games. In particular, the specifics behind the GS Ball were very cool. A woman called Chieko would interact with the player via the machine, quizzing them on their philosophy as a trainer:
1) Should Pokémon be protect and rescue people other than their owners? [Yes]
2) If a Pokémon is afraid of a person, is it the person's fault? [Yes]
3) Is there a goal for a person who likes Pokémon beside being a trainer? [Yes]
4) Is a child a weaker trainer than an adult is? [No]
5) Do you think that the legends from the days of old are all a lie? [No]
If the player answered all five questions correctly, he was said to be a "splendid trainer with a strong, right heart" and was then given the GS Ball by the nurse upon leaving the PCC assuming that they had 16 badges (only this was part was localized). Even after the Ilex Forest event, Chieko stayed in the center to give the player another shot at her mini-game, giving them three Apricorns if they won. In fact, she revealed that she was a "ball meister" like Kurt. Since Kurt's granddaughter was called Chie in Japanese, I suspect that Chieko was Chie from the future.
I suppose that if it hadn't been for the Mobile Adapter, Crystal would have had more offline content. But I appreciate what Game Freak pulled off in Japan, and I enjoyed the extra lore, Kris and animated sprites.
For general Mobile Adapter information:
https://daily.pokecommunity.com/2018/01/19/pokemon-crystals-online-service/