Yes, QNAP is using the Thunderbolt networking feature - I have mixed feelings about that (it has the unpleasant feature of grabbing control of the Thunderbolt bus, but pleasantly it is much less of a problem on sudden disconnect than an enclosure)... You care much more about it grabbing the bus if you have a Mac with only one Thunderbolt port, because you can't daisy-chain anything to the QNAP. With two or more ports, simply put displays and/or other drives on a different port (this works very well on a 2015 MBP). They say it's actually 20 gigabits per second, not 10 (WHAT kind of disks would it take to test that???).
The fact that it has a computer inside enables a couple of really nice features - it can back itself up with no interference from an external computer (mine has its own WD MyBook attached via USB, and it keeps a copy of itself on the MyBook updated daily). It'll do this even if I'm out of town for a week with my laptop. It's also accessible over the Internet like any other NAS - not at the blazing speed of a Thunderbolt connection, but try that with a G-tech RAID. A secondary feature, but a nice one, is that it'll control a UPS and shut itself down in a controlled manner if the power fails, resuming on its own when the power comes back. You can sort of get an enclosure to do that if you have it set to power up and down with the computer , and the computer is controlling the UPS(if the computer's not a laptop - a laptop will hum merrily along on its internal battery while the enclosure drains the UPS).
The Thunderbolt connection saves at least $400 over trying to get a Mac to talk 10 Gb Ethernet ($1000 or more if you want to include a switch in the network)... I agree with Joe that it's basically a 10 Gb NAS that can run its network over Thunderbolt - but that's a crucial advantage if you have Macs, since the only way to get a Mac on 10 Gb Ethernet (other than an ancient Mac Pro with slots) is with an expensive Thunderbolt to 10 Gb adapter...
So far, I haven't seen any major disadvantage to the QNAP compared to a conventional Thunderbolt RAID on a similar scale, and it's not more expensive than a good one (it IS more expensive than the low-end soft RAIDs like the Thunderbay series, but it's very competitive with higher-end LaCies and G-Techs).
One day, Apple will make an iMac with 10 Gb Ethernet (who knows, maybe they'll put out a reasonably priced Thunderbolt to 10 Gb dongle at the same time), and then a regular 10 Gb NAS will work for creative pros (at least, as they upgrade their computers) - until then, kudos to QNAP for this odd machine.