Those were discussed somewhere recently. I can't remember if it was here or another fourm.
Given that 1st quality POC arrow shafts you buy these days aren't always the best shafts, and the 2nd quality "stumper" shafts are really pretty bad, these things, which the company making shafts has considered to be too poor quality for arrow shafts, must be really bad.
Yes, they're cheap, but I'd be surprised if they were suitable for more than garden stakes. Besides, if they're sold as garden stakes, and you use them as arrow shafts, you're sidestepping the PR fund tax that is supposed to go to our wildlife.
Guy