Benefits of a "streaming hub"?

Thanks for your comments. I read up on all this and it seems I can benefit from a server. Even so, some people state the iMac is fine. But it seems reasonable that a server will constitute an improvement. Thanks again.

It WILL sound better than a computer because it is built for audio.

It all depends on what you mean by "streaming."  

Many think of it as a player that will connect to the internet and play songs from your Tidal, Qobuz or Spotify (etc.) account.  

Others think of it as a way to put the PC or device holding your local collection of music files in a room away from your stereo and "stream" the music over ethernet or wireless to a separate player attached to your system.  

Many setups will do both -- stream your local collection and also the internet music services. And, they will also often support multiple players so your collection on the PC can be played on multiple stereos in different rooms -- some can also sync the players.  These system are often controlled by apps that can be installed on your phone or tablet so you don't have to go over to the stereo to start the music or change songs. . 

If you read the forums, there are lots of different options for doing this and many price points from inexpensive to very expensive.  

Besides looking for a device that delivers the level of sound quality you want, the other big thing to look for is a user interface that you find easy-to-use and intuitive -- you want to be able to find and play your music without a fistfight.