There is a chain and the system is only as strong as its weakest link. And a quality DAC differentiates itself in execution of bits to music.
A quality DAC will take the best streaming, audio files and deliver great sound but just as critically it will take MP3 and bluetooth and present a cohesive sound.
I use a DAS and have no doubt a music server will do the same. The analogy I made up (and it could be wrong) is a quality turntable is the basis of using a higher quality cartridge or tonearm and even phono stage. Lack of the quality table and the stuff down the chain doesn't work. (of course someone can say without a phono preamplifier it means nothing - lets just leave that out for this example).