Doesn’t look more durable to me..
https://forums.macrumors.com/threads/iphone-x-flakegate-iphone-x-space-grey-finish-flaking.2088863/
Because the space grey has a protective coating, its more resistant to knicks and scratches but the downside is you csnt polish it without removing the coating
So it is more durable but it is less fixable vs silver