It's FAKE ! No one cable can convert digital signal(s) to analog.
It's weird. At first I thought maybe it was one of those devices that has the two connection types and the hardware that does the digital/analog conversion just wasn't shown... but reading the description it sure does sound like the link claims to be just a cable.
The bad part is that a lot of people will probably get sucked in by a link like that, thinking "hey, finally a cable"... when, as you said, it can't possibly be done with just a cable.