If someone is sure they only want an e reader then a significantly cheaper single purpose device is, imho, the far better way to go or go for the oldest Mini available at the Apple refurb store.
I’ve used the Mini (4 now I have the 6) for ereading for several years. When I first bought it, e reading was the main reason why. I was able to get a Walmart deal so I got the base 4 up in the 200s. Still well above the good Amazon e readers but i considered potential future uses (along with the preference for Apple products). And that’s the big caveat I’d highlight when weighing cost: what you may/can do with a small tablet device. The Mini eventually became my almost everything device that easily goes most any place. Netflix watching, emails, games, web surfing, FaceTime, social stocks and financial app usage, Notes, calendar, even rare photo taking — now sitting very well between my laptop and smartphone. Just laying on the couch, lounging in bed, on a plane, anywhere you’ll be lounging around — it grew very nicely into its higher than e reader cost with the add on functionalities.
The new mini is expensive, no doubt. So I can understandably see a pass for some (the trade in made it easier on price for me). But the Mini 6 is a significant jump from the 4. The GF sticks with her Mini 4 (waiting for a good sale). So I can see it side by side. Starkly better Audio, video, speed with a smaller form factor yet slightly bigger screen (though I liked mini 4’s easier gripper big bezel).