Jitter results in frequency domain errors, not *just* time domain.
Though it is a clock issue, the overall conversion is affected because the DAC is using the clock to reconstruct the original signal.
The ear can reliably detect timing errors up to about 0.5ms (equivalent to the click you hear when a stylus hits a small speck of dust on a record). This is 500,000 ns, well beyond jitter figures exhibited by the worst systems.
Jitter is completely (read: not maybe) eliminated by clocking the transport and DAC with the same master clock. This requires both to have a word clock input, not easy or cheap to implement. Which is possibly why very few of the big-dollar companies offer it in their mainstream products, reserving it for their highest-end products.
For those with pro audio cards as transport, the SPDIF input can be used to feed a clock signal (with some skullduggery) to the transmitter chip.