iOS - Different images based on device OR scaling the same image?

It seems that developers always create different image assets for different devices and load them based on the device. But are there any drawbacks to just creating images for the largest resolution device (iPad) and then scaling that image down for iPhone 6, 5, etc?

I use SpriteKit, so I would just create SKSpriteNodes of different sizes and apply the same texture to them and scale it to fit the node.

I know that performance can be something to consider (loading large images for older devices). But that aside, is there anything else? Would these images appear more pixelated/blurry?