Teleportation is the little death that avoids total obliteration. It allows you to move around the level quickly, and instantly escape from dangerous situations (often to the dismay of your opponent who was about to kill you). It's mechanically very similar to dying: both take you out of the game for a little while, during which you can move around the level to look at stuff, and then spawn at your selected location.
Originally, when you died, you couldn't do anything until you respawned at a random vertex. This was too much of a punishment - there needs to be an advantage gained by killing enemies, but being unable to do anything for a while is just frustrating. Being able to look around while dead helped a lot, because the game is still responding to input and you still feel involved, but ultimately I decided to allow selecting your respawn location. It was difficult, because I worried that the advantage from killing a player would be too little, but it turns out I was wrong; the time spent dead and the loss of colour energy are far more significant than the nuisance of not being where you want to be. And because teleporting takes much less time and doesn't stop you gaining energy, it's still way better than dying.