Thats because Abzan decks are all about surviving the early turns to gain a significant advantage in the lategame
While specific, a flying mana dork is already not a bad get - but theres more
This is why you see flicker effects that exile permanents, because they leave and return as a new object
Conspiracy cards aren't spells since they cant be played, they exist only in your command zone
As a rule of thumb, Ive found that if the card(s) in question cannot win you the game outright, the answer is usually No. Cards like Insurrection, Finale of Devastation, Rise of the Dark Realms, Armageddon, and Expropriate are cards that often belong to this category, and should be added very sparingly to your deck