Back when Macbook airs had tiny drives and sdcard slots, there were multiple vendors selling flush-mount sd cards. They work surprisingly well, they can sink heat well into the aluminum body.
This product isn't quite there yet, but it's clearly aiming for the same market.
It's a portable device, everything on it needs be backed up frequently in case of loss or theft anyway.
I just wanted more storage for media for when I'm not connected to my home setup and/or into a fast internet pipe, and also didn't want to pay apple 1000% margin for 2 commodity flash chips.
This product isn't quite there yet, but it's clearly aiming for the same market.