Saying that just adding new content with new rewards is a "seasonal element" seems very silly to me, and it reduces the definition to meaninglessness. If adding new content is a "seasonal element" then we could say Elden Ring has "seasonal elements" because it got an expansion. I don't understand the point of making the term that absurdly broad, much like I don't think it would be valuable to say every game where you play as a character has "RPG elements" just because you play as a character in an RPG.