Why would I need Roon?

I have a Blue sound streamer with plenty of files at my fingertips, via a hard drive plugged in the back and multiple streaming services. Can someone help me understand what Roon would add to my set-up? Thanks. 
How are you using Roon Radio? I thought it just made a station based on the last song played which wouldn't be diverse enough for me (I like a lot of different stuff). I'd like a station based on multiple artists or my favorites (like Deezer and Spotify can do).
FAQ: What's Radio and how does it work?What is Roon Radio?

Designed from the ground up with machine learning technology, Roon Radio can play a mix of your favorites along with music from beyond your library, using the vast catalog of music from TIDAL and Qobuz.

Roon Radio makes recommendations based on not only your own music preferences but also those of other Roon subscribers with similar tastes in music. Use the thumbs up and down buttons to craft a personal, one-of-a-kind radio experience.

As you listen to and interact with Roon Radio over time, it learns more about what you like and helps you discover new music by curating great recommendations.

How do I start playing Roon Radio?

You can choose to start Roon Radio any time by navigating to an Artist, Album, or Track and choosing the Roon Radio playback option. Roon Radio uses this initial selection to queue up similar tracks.

By default, Roon Radio will also start once your current queued content has finished playing. This can be seen on the Queue screen, and you can turn this feature on and off from there.

How do I customize my Roon Radio queue?

Once Roon Radio has started, you can head over to the Queue to view upcoming track selections. If you see something you like, give it a thumbs up to add the track to the queue. Clicking thumbs down will skip that track and generate another recommendation, but you don't have to make any selection if you don’t want to --- once the current track has finished the next selection will start playing automatically.

When you skip a track, you can optionally choose why you decided to skip the selection. This data will help us improve Roon Radio over time as more data is gathered.

Upcoming track information will also be displayed in a pop-up toward the end of the current track. You can disable this notification by going to Settings | Setup | Enable Roon Radio Notification.

Roon Radio FAQsCan I set quality requirements for Roon Radio selections?

For a given track, there may be many different versions, including different sample rates, between what is available in your local library, TIDAL, and Qobuz. Our selections are based on what version is the most popular, even if there are potentially versions with a higher sample rate available. At this time that is not something that can be changed.

Can I set Roon Radio to only pick tracks from my library?

Yes. On the Queue screen choose the 3 dots option and select Limit Roon Radio to Library.

Can I filter out tracks with explicit lyrics?

You can filter out explicit content by going to the Queue screen and choosing Filter Explicit Content in Roon Radio from the 3 dots menu.

Please note that, while we do our best to filter out all explicit lyrics, the quality of this data is highly variable and we might not always know if a given track is explicit.

What if I don't have TIDAL or Qobuz?

If you don't have a streaming service connected in Roon you can still use Roon Radio. In this case, Roon Radio will be limited to your local library and does not take advantage of our machine learning technology. We recommend using TIDAL or Qobuz for the best Roon Radio experience.

All this and more can be found here:https://kb.roonlabs.com/Roon_User_Guide#Browsing_and_Playing_Music
@twb2 - thanks for providing the FAQ.  Unfortunately, it doesn't quite do what I said.  It will only play songs similar to the artist chosen when Roon radio started.  It even says "Playing music similar to..."  There's no way to choose a wide range of music types that can be done in Deezer, Spotify and GPM.