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
One could argue that the same applies to a PSA 10 version of Time Walk that was sold for $63,000, or a PSA-10 MTG Black Lotus sold for $3 million, but that's not exactly true
In most cases, this doesn't make the biggest difference, and it's probably worth playing another support instead
Most Arcane Signets can be acquired for just under 50 cents, but the borderless Fallout Signets have unique art that refers to a beloved artifact of the Fallout universe, the Pip-Boy
Its owner puts it on their choice of the top or bottom of their library
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)