Standalone audio streamers are interim solutions for those who do not yet have AVRs or pre/pros with that functionality already built into them. I'd consider them the modern equivalent of the separate AM/FM tuners which used to be readily available for hifi systems a few decades ago. Unfortunately, I suspect their viability will be even shorter. One of their omissions is that they do not support video streaming. Similar audio (and static image) streaming functionality is provided in most current AVRs and pre/pro models, including those available from D+M.
Alternatively, if your current receiver has HDMI inputs, one can add extensive streaming support for both audio and video by getting a Blu-ray player like those from Sony or Oppo. Sony's streaming support is somewhat more versatile than what's available in other BDPs. Other solutions are available in the form of AppleTV, Roku, and other HDMI-connected streamers.