In most cases, this doesn't make the biggest difference, and it's probably worth playing another support instead
If you get Fall of Cair Andros on the battlefield, any excess noncombat damage you deal to an opponent's creatures will turn into a bigger Army
Creature - Dragon Color tag templates(None) Hellkite Tyrant Flying, trample Whenever this creature deals combat damage to a player, gain control of all artifacts that player controls
In addition to the normal rules regarding winning and losing the game, the Commander format has one other rule: a player who has been dealt 21 or more combat damage by the same commander over the course of the game loses the game
Making a 3/3 flier when you gain three life is no joke, and giving flying to other big-sized ground creatures is an awesome ability
SAR specifically tends to sit in the upper-middle range of the secret-rare numbering (often the top third of the extended checklist past the base set)