I personally don’t see a difference between the same model new and used without any noticable damage. Is 30% of the price worth for the ‘new’ status?
Some resellers even sell like-new/mint/open-box/refurbished as new.
If the device works just fine as the new one, getting used not only saves you cash, but also holds value better. If you decide to sell it later, it has probably devalued less. If the model is faulty, you’d lose less when the used device failed vs the new device.
Now you could argue, what about the newer generation? Probably a year or so old is a saner choice. Laptops, cars and phones all get small incremental upgrades. Is the 20-40% price worth the slightly faster or larger or better product? You probably won’t even notice. But you will, what you can buy with the cash saved.