There has to be a very niche market for people who want ChromeOS on their device but do not have the technical know-how to do so, or without a device that can flash an iso.
I guess for $3 it's not really a cash-grab or anything. Kinda nice to see vendor-supported live USBs honestly
I'd say the majority of people don't know how to install an OS on a device and having the ability to run Chrome on what is likely e-waste is a good thing.
I applaud the efforts of people/groups like MrChromeBox who figure out how to flash linux onto Chromebooks. There are great designs like the Samsung Galaxy book in red with Amoled display (thin metal body) unfortunately it only has 8GB of ram.
It kind of makes sense for it to be a partnership with Back Market, which also sells used hardware.
That way, the ChromeOS USB key can be an add on to the purchase of some old laptop that can barely run Windows anymore.