Why not HDMI or similar for hi-end audio?

I run PS Audio transport into an upgraded Wyred 4 Sound DAC2 SE via I2S connection which uses an HDMI cable

I use HDMI for virtually all of my listening, sounds very good to me. The only bummer is that the connecting cable is prone to backing itself out, resulting in no signal transfer at all. But it's very easy to fix...

-RW-

Thanks guys; I'm thinking to preamp and amp and maybe even speaker cables!