In the first picture the color comes from a sampled drumset where each part of the drum has a certain color, like kicks are red, toms are orange and snares are yellow.
In other cases you can see which keys are going to play a sound at all and you can see things like keyswitches (Those are used in certain sample libraries for violins and stuff like that where you have a few playstyles to choose from).
You can also set those lights to indicate certain scales, so you know which notes are part of the scale and which aren't.
But yeah, I'd say it's most useful for sample libraries where you have a variety of different sounds mapped across the keyboard at once.
Beside of those things, it just looks damn awesome
Nope, it's a bit hard to explain, but I'll try my best:
Launchpad
The Launchpad has 64 pads and was made with perfect support for Ableton Live in mind. Live allows you to trigger certain scenes or midiclips which is quite useful for live performances. The Launchpad allows you to trigger those scenes and stuff. It also has a keyboard mode, where each pad is one note and a mixing related mode, where each row is a volume fader or something like that.
The thing I have is called "Maschine Studio".
Maschine Studio
The official term for this kind of thing is groove production system, and it's pretty much made for making beats (Each pad is one sound, like a kick drum or snare and then you can enter a sequencer mode for each of that where you can place those sounds on a grid). Beside of that it also has a few modes the launchpad has as well, like a mixer mode and keyboard mode, but thanks to its software and displays you don't really have to look at your pc at any time, since you can also browse and load every instrument you need.
It also has dedicated play and record buttons as well as knobs for tweaking synth settings and stuff. In short you can build a whole song with only using this thing.
I guess the video explains it a bit better at around 0:36