>>57004077I am probably being autistic about it but stuff like super training, surfing and curry cooking are all tied to core game mechanics. They are more or less optional but they are not really a side activity. If you want good stats or certain pokemon or moves, you have to do them.
Stuff like the underground or the pokeathlon are more like leisure activities. They are not part of the rpg grind. They have nothing to do with the battle system and the rewards they give are all stuff you can get elsewhere for the most part.