It seems as if efficacy of this device is questionable. It helps in some cases, hurts in others, such as with high end DACs that reclock everything. With a linear power supply some induced noise is reduced, but now you’ll add another couple of hundred bucks to this $150 device.
The question is, how will this work with a PS Audio DAC? I know some people here have had good results. It’d be nice if we could get this tested. 
It worked pretty well for me. Better than a ISO Regen on USB with LPS 1 power supply on USB in terms of results.
I am using the bundled iFi iPower on the iPurifier.
I guess it depends on the gear.
I don’t think running the stock iFi power supply into the coax is a good idea since that power supply has awful AC leakage properties.
I use the purifier for optical and get really good results placing in between optical out of my tv and my SGCD. In this implementation, there is no electrical noise or leakage from iFi power supply but you get a better optical signal for the DAC. Even when running optical the power supply matters a lot. I tried a cheap Jameco linear wall wart instead of the iFi wall wart and sound degraded noticeably.