Of course, everything is. Doubling the speed of light means your network packets get there twice as fast, but accelerating matter to relativistic speeds, which

Of course, everything is. Doubling the speed of light means your network packets get there twice as fast, but accelerating matter to relativistic speeds, which too is limited by the speed of light, has less marginal utility from the doubling when it comes to energy needed for acceleration/deceleration and time dilation.