It still doesn't cut down on cables since you still have to plug the cables in this dock. So instead of connecting it to your computer you connect it to the dock. It's a hub.
That's not what a dock is for. A hub only connects one type of interface. A network hub connects one network connection with several, a USB hub connects one USB connection with several, etc. etc.
What this is for, and the reason it's called a 'docking station' (going back to the 90's and early 2000's when laptops had a dock you'd connect them to that did just this), is because it's for thunderbolt equipped laptops. You work with your laptop on the go, spend all day with it, etc. Then you come home, set it at your desk, plug in ONE cable (plus the charger), and you have your monitor (You can still use an adapter at the end of your thunderbolt chain to connect it to a non thunderbolt monitor, or use it as a mini Displayport port), your external hard drives, a wired keyboard and mouse if you have one, etc.
As it is right now, I plug my laptop into a mini DisplayPort monitor (Apple display), a USB 3.0 Hub, MagSafe, and Optical Audio. The hubs (display is a USB 2.0 hub) connect my iPhone, an external drive, an external DVD drive (I have the optical bay replaced with a second SSD), a beloved wired mouse that I have had for more than 10 years that I simply won't do without, an iPad, etc. Optical audio goes to my sound system, etc. I also connect it to GbE occasionally, especially when I have a large time machine backup or need to move large files across my network (it's over twice as fast as Wireless N in dual 5GHz mode)
A dock, in theory, could replace 5 connections to my laptop, with just one. Nifty huh? It's a convenience thing, many don't want to pay for that convenience, but some do. It also ADDS ports without adapters. Many Mac laptops no longer have ethernet, some of us still use it at our desks because it's faster. When Wireless ac comes out, if it delivers the promised speeds, that'll change. But for now, I can't imagine moving gigabytes worth of files over WiFi when I'm at a fixed location (my desk) which has a small gigabit switch right on it that runs back to my router. It also adds FireWire, and some of these Docks also add DVI-D or HDMI. All of these things can be had with adapters or dongles, but the dock replaces all of those dongles AND doesn't tie up ports on your MacBook with dongles, and allows one plug to connect and disconnect.
One thing I'd wish they'd do, is make them 'smart', in the sense that external drives would 'mount' to the dock, and not the computer. Similar to the way you 'mount' a network drive. If you lose your connection to the network drive, it won't damage or corrupt the drive. If the docks did this, it would add a level of convenience. As it is now, I have to remember to unmount my drives before disconnecting to go mobile.
-John