On the Technical Specifications page for the iPhone 7, Apple suggests that users who would be bothered by these scratches should use an iPhone case.
The high-gloss finish of the jet black iPhone 7 is achieved through a precision nine-step anodization and polishing process. Its surface is equally as hard as other anodized Apple products; however, its high shine may show fine micro-abrasions with use. If you are concerned about this, we suggest you use one of the many cases available to protect your iPhone.
Presumably, the finish should hold up at least as well as the finish on the iPhone 3G and iPhone 3GS but we'll have to wait until we get one in hand to offer more details. Please follow iClarified on Twitter, Facebook, Google+, or RSS for updates.