I wouldn't say they are not good, just that when spending $50 on an eyepiece you need to have your level of expectation set first. $50 is not a lot of money for a manufacturer to sell an eyepiece, so there will be cuts in material quality and workmanship that goes into making it.
You may be correct. However for $40 listed, I may try one to see how it is. If I don’t like it, even selling it for half of what I paid is only $20. Not a noticeable loss compared to selling other equipment I’ve sold in the past.