With a slight modification to your quote, there are unfortunately quite a lot of things in Pokémon that this applies to. Fill in the blank with any type of Doubles strategy, a decent chunk of the Pokédex in any given game, many held items or TMs, evolution methods, or certain configurations for Pokémon that are otherwise trash (whether it be held items, abilities, or moves the Pokémon sorely needs to function).
One of the most fun things about the Pokémon games is that there are so many ways to play them. Yet there's also a bunch of stuff you effectively can't play with, because you only get them when the game is completely depleted of casual things to do. Take some of the Megas in Gen VII, for instance, where you have to have gotten pretty good at the Battle Tree to unlock them, and by that point, the only thing to do with them is more Battle Tree I guess. Unless you're very into that, tough luck. For instance, do you think Mega Beedrill is awesome, but only play Pokémon for the main story? Too bad. You can use it for the very final leg of ORAS, I suppose, if you go out of your way for it. Otherwise, no sell.
I suppose this is kind of inevitable given the core design of Pokémon. Still a bit of a bummer, though, if you're not ready for it, and the games rarely try to soften the blow either. I'm still kind of pissed about trying to use Solosis in Sword and Shield, where you can see its location fairly early (Bede has it in his first fight, so you can check its location right after that), but the game completely neglects to tell you that the weather required for it to appear only appears in the postgame.