Note: the following theory is the brain child of an anon on /sug/. I do not claim responsibility for this theory, only for this explanation and a minor modification of its framing
I’m sure by now a lot of you have seen Slowpphire the adorable pink sapphire whose grasp of the future seems a few minutes out date. Between her quirky defect, her top-notch character design and her tentative shipping with Pink!Lars she’s taken the fandom by storm, and leaving a trail of destruction in her wake the FEMA seems disinterested in attending to.
Fans were hasty to catch on to Slowpphire’s defective future vision and nickname her based on the assumption that her sight is out of sync by a matter of minutes. But first glances can be deceiving, and Slowpphire’s ability may not be what it seems.
Seeing the future from a few minutes ago is a disability as far as Sapphires go, but if Sapphires were designed for short term prediction alone they would not be valuable enough to be considered Upper Crust. If this Sapphire is considered a defective outcast on par with pair of conjoined twins, a mixed-gem fusion containing a pearl and whatever that monstrous gem centipede is, it suggests that her defect is far more debilitating than a syncing issue. Slowpphire doesn’t have future vision, she has Past Vision!
As far as super powers go, postcognition generally stands on the power tier beneath such classics as talking to fish, detachable arms, and having giant sticky grapes for hair. The ability to see the past is useless to those of us who are confined to the present, and though homeworld has access to at least two forms Faster Than Light travel and a time machine it’s pretty clear from where I’m standing that gems try to avoid fucking with the timeline.
However, even useless superpowers can be handy if used correctly, and Slowpphire is no exception. You see, hindsight can’t tell you what comes next, but it can tell you what happened, and in all of Steven Universe the greatest remaining mystery to both the viewers and Steven is a question of what happened. Pink Sapphire can show us what happened to Pink Diamond!
Yes, I said show. Any old enough gem can tell Steven what happened, but words are limited, memories unreliable and the crystal gems have proved themselves deceitful when it comes to sheltering Steven. Slowpphire and Slowpphire alone can show Steven what happened that night, all she needs to do is pass her vision on to him, something we’ve seen Garnet do twice in the past, and he can open his eyes and watch as a diamond falls before him