Why not? As long as you discount the price of the new product by the perceived value of new vs used, that’s the correct comparison to make. If a used product is the same quality and $100 cheaper, and just having something that’s new is not worth $100 to you, you should pick the used option. The goal is to get the best value per money spent.

mental gymnastics; used is not new. even new isn't necessarily new when it's not sold by an authorized seller because it can invalidate the warranty.

new is new and has legal ramifications, you cannot compare them unless you're throwing in a trustworthy extended warranty that matches -- and pretty much nothing matches apple in that regard

Well you have to consider the differences but you can absolutely compare them when you want to decide what you buy.