One thing that playing KSP taught me is that fuel consumption is *everything* in long range space travel. Once you've got something in orbit, the fuel-weight-to-delta-v ratio is literally the only thing determining whether your craft can reach any location at any desired speed, up to and including relativistic speeds.

You don't need a lot of thrust to do that. In KSP, you can build a ship that can work like Star Trek, i.e., forget about orbits and such, just point at a planet and press the throttle until you're there, with only reaction control thrusters as its main engines. The trick is that you have to turn on the infinite fuel cheat to do it, so that you can burn for long periods. Just keep burning, and the velocities keep piling on until you're going as fast as you want to go. (Though you still have to burn the opposite direction for the same amount of time to stop.)

That's why, if the EM drive works, it's a big deal: It would essentially solve the fuel problem if it were true.

I don't think the EM drive works as they think it does, though. Any time scientists say "this would overturn the laws of <insert name of discipline here> as we know it", it's time to get real skeptical and start to demand overwhelming evidence.