Those cards are at their literal best here, as theres no floor lower than 0/0 for them to change (except for that one card)
In case Arcades is removed, his Commander deck has cards like Assault Formation to keep the defenders online, and the deck can even "flicker" its defenders so ETB effects like Arcades' own can be used all over again
Due to the standard play not providing a very optimal way of farming cards so you rely on playing events in which you have to win a certain amount to really make a profit and for that those decks arent good enough in my opinion
Outside my own builds I've never even seen a ring in a top8 deck list photo
I am comfortable with it on the sideboard, too
With vigilance, reach, trample, and haste, Titania can quickly overwhelm your opponent