>>34682166Tailwind and Trickroom only require you to EV and maybe breed a Pokemon in a certain way to benefit from the move.
To benefit from weather or terrain, you need to SELECT pokemon which are individually less powerful, but synergize with the battlefield thanks to their abilities and/or types. However, this puts them at a disadvantage outside of that weather/terrain and makes team synergies more awkward. (for example, a rain team with Pelipper, Ludicolo and Mega Swampert is running 3 water types. That can be bad, if your opponent has something to counter water or doesn't care about water)
The weakness of Trick Room/tailwind, is that it needs to be setup before it can do anything, which gives counterplay by knocking out or taunting the trick-room setter.
Most of this is more relevant to doubles than singles, but keep in mind that Smogon exists because the Pokemon people don't give a flying shit about single battle balance. VGC is the only supported format and the one these games are balanced around.
