I haven’t opened my SG for this ridiculous split as well.
Considerations:
Silver is nostalgic, and a tribute to iPhone's history.
Silver may become a nice collector's item - if you collect phones. But at the end 3-4years, they all become paperweights in your drawer or collector's box. Still, for some people, a thing that marks the 10th anniversary of a technological marvel, and is designed with all the best nostalgic elements into one great package is a nice artifact in history. In 50yrs time, they might hold same vintage status as the original Macintosh.
Silver is a triumph of form over function
It's beautiful, it's attention-grabbing, and highly impractical. That is, if you consider scratches on a glossy surface impractical. One can argue that it's just part of using/enjoying a nicely designed thing. And there's always the plethora of cases, if you want to keep it clean.
If you can ignore the scratches that will happen, the silver is deeply true to Apple's DNA. Impeccable design for high technology brought to the masses. I think this may be the most beautiful thing Apple has ever made.
Space Grey is understated beauty
Space Grey is for those who like a very clean, uniform, seamless looking design. This was first seen on iPhone 3G, and then again with iPhone 7 Jet Black. There's no denying the appeal of something that looks like a solid black monolith with insanely dense amount of tech crammed into it. Similar applies to the Silver, but the seamless black look makes it feel like you're holding a magical slab of solid rock. This is Neat.
Space Grey also has PVD coating, which offers some small degree of extra protection. Hardly worth mentioning, but I did notice much fewer scratches, if any, on the store SG display models.