I've got one. Tried it and it does work - sort of.
But the card software didn't let me upload files to the card just download. Not much use.
Also it auto shut off after a perid of time. Also not that useful.
But I could connect to it and it did work in the sd slot.

Given that my main printer is 12 inches from the card reader and the other is connected via usb as well.
I don't actually need it.

Might try it again when I move one of the machines into the house for a couple weeks next month.

Although given that I'll still need to be by the machine for the first layer. What's the point lol
might just as well write to card and take card with me.

I can see it being useful if you have a number of machines.

I think it's a toshiba card I've got.
I might have another go.