@Erikari
That's up to whoever decides how the effects should be implemented in the game.
It also usually depends on whether the effects and the character/thing that caused them should move or behave independently or not. (eg, should one stop, when the other stops? should one stay where it is, when the other moves away?)
And beyond that, use whatever technique looks nice and fits in the game dev budget (time, money, memory, and any other technical budget).
