The word clock will reduce jitter when compared to a non-clocked data stream. However, if the risetimes are slow, there will still be jitter generated at the DAC. The transmission-lines must be well-matched to prevent reflections.
It will eliminate any data-dependent dispersion due to lossy cables. You can use a cheaper cable with good results.
It will eliminate any data-dependent dispersion due to lossy cables. You can use a cheaper cable with good results.