They certainly are! To think, as a kid, in the 1980s (yes, I'm still a kid)... LEDs were cool, but kinda limited. Now, holy moley, these things are really spiffy.
My original order was 120 of them, and I'm likely not going to use all of those for the Matrices. My thinking is, with the technique I'm using to make them easier to handle, they should be pretty easy to mix into costume pieces. A little chunk of protoboard roughly the size of a quarter that emits light in any color I tell it to, that I can wear? WOW!
Yeah, I know, I could order wearable-specific components from somewhere like AdaFruit. Don't be mistaken, I love AdaFruit, and what they do... I just like being stubborn and making some stuff myself.
That said, I'm still waiting for my Arduino clones, and getting all of these tiny little buggers protoboarded. I ordered three controllers, and since two are going into Matrices, I may finally do something with all of these servos. I got a 10 pack of 9g micro-servos recently for a steal, and I'm itching to build another little robot.