I have the one you linked. I love it! Saves so much time.I don't think that charger will charge all batteries at the same time. It will still take just as long to charge as you would charge one at a time. Do let me know but I think that's how they work. If it's using your same charger, it's only rated at a max watt out. Now, if you go with something like this, then each connector has similar out power as one charger.
DJI Phantom 3 Battery And Transmitter Charger Plates 110-240V Input 4 In 1
On a side note I ordered mine from Banggood as well, the first one I got did not work. I emailed them about the problem and they sent me a new one without even sending the old one back.
So as far as Banggood I was very impressed with there customer service, and the replacement sent has performed flawlessly