Yes, but the point was that it would be far more optimal to have the control signals go directly to the LED driver circuitry instead of chopping up the mains voltage and hoping that the LED driver will handle it.
Computer analogy: Imagine you would like to adjust the performance/power of your computer. You could plug the computer to a dimmer and then engineer the computer to adjust itself according to the dimmed mains voltage. Or you could route the X10 signal to the computer and use it to adjust the power profile. Which solution seems more reasonable to you?
Personally I think PLC based system would make most sense for home automation, considering that a large portion of the devices are mains-powered anyways. And if you design the system really cleverly then having the same network extend wirelessly to those nodes where PLC is unsuitable.
Powerline control is fine, but X10 is simply too slow to handle the demands of a modern house with advanced automation. My own system uses DMX-512 and Philips Hue lights (which use Zigbee Light Link). Some of my customers use X10, but the performance is not nearly as good since it can only transmit 20 bits per second.
Most dimmers, X10 based or directly controlled, are based on chopping the voltage not completely unlike PWM. They are called "triac dimmers". But irregardless how the dimming is implemented, the effective (RMS) voltage is changed. But in addition to lowering the voltage standard triac dimmers also create problems as the dimmed voltage waveform isn't sinewave anymore.
If you have already X10 system in place, wouldn't X10 compatibility be more ideal than dimmer compatibility?