If you were smart enough to figure it out you would realise that my argument is not invalid, your argument is that you cannot earn something from xur because you have purchased it with strange coins which you earn from work, I say that means you can't earn an Xbox by that logic either, by doing work in any way to get an Xbox you are doing the same, you're just getting an Xbox at the end of it instead of money, which in my argument you would have used to purchase an Xbox, you just skipped the purchasing step. Argument is still valid.