Play-from-tray as a playstyle means focusing almost entirely upon powers, specializing on doing most of your damage with powers while minimizing any weapon use. The weapon playstyle, naturally, is the inverse; almost all of your points go into maximizing weapon damage and your powers are secondary at best. The goal is to ensure that damage-oriented players can be dealing just as much damage using a powers-only approach, a weapons-only approach, or the usual hybrid build. Check out the latest dispatch for more details on how everything is being balanced.
DC Universe Online overhauls its stats, it’s helpful to know how the game actually expects players to play the game. The answer as of the latest revamp rundown is that you get to choose, but there are three main playstyles that the game is being built and balanced around. The hybrid playstyle is the “default” style and the one that most players are likely familiar with, but the play-from-tray and weapon styles are a bit more unusual, especially when one considers that all three playstyles are meant to have roughly similar performance.
Source: Official Site