While Ruby/Amethyst probably has the advantage realistically in that matchup, its not by a lot and a strong Sapphire/Steel player can certainly overcome Ruby/Amethysts tools either by gaining more cards in hand through superior draw support, or discarding that decks key cards via A Whole New World
This sort of thing isn't terribly new, either
If youve got a reliable way to turn permanents face-up, Yedora, Grave Gardener can keep your board unkillable
Thinking of an idea and trying to translate it to Magic is rarely going to feel more organic than something that starts with Magic and its gameplay already in mind
Now, if this card was an Aura, it would probably just move when the enchanted creature dies, but as it's an Equipment, it became a little trickier
It goes even further in decks that can blink permanents