Am I missing something?
If you have to load them via wire transfer, then you're not anonymous any more, unless the account you use to load them is also anonymous. But in that case, you would likely already have an anonymous card anyway.
So... what's the point?
You are missing this:
These cards can be used to cashout from exchange services, paypal, skrill, etc...
You give them your IBAN and they load the card.
If you were anonymous before you remain anonymous.
I think you can also send from Western Union (and maybe Moneygram??) directly to IBAN. I never used WU or MG, but if you don't have to show ID you remain anonymous.