It’s easiest to think of Roon as two parts of one whole.
The easiest part to understand is the role of Roon an an extremely flexible, high-quality, “player” (and “server”), with built-in capabilities for DSP, EQ, upsampling and on-the-fly format conversion, as well as full control of a multi-node, multi-room system, remote/network audio players*.
And it can combine your local library with albums and tracks from Tidal and make it appear to be one seamless library, which is displayed in a rich, beautiful and fluid interface
But the best features of it, in my opinion, come down to how it exposes your music collection.
It provides an expanded set of metadata, background information, and links to other music, data, profiles, bios, histories and so on based on that metadata. This takes things well beyond the basic embedded data in most digital music files and provides a very rich view of your library.
When you engage “Focus” mode on something, you’ll get to explore that, say, album in detail - including related works, histories, deeper insight into the recording itself and the band/group/orchestra/artist etc. This is an amazing avenue both to explore and understand your existing music collection more deeply and, perhaps just as importantly, to discover new music.
Roon can run all on one machine if you want to. Or you can run a separate “Core” and have multiple control and end-points spread across your network. The “control” point looks like a high-end media player/library manager, and is very visual. That control point (a PC, Mac, tablet etc.) can also be an “end-point”. End-points actually output the music to, say, your DAC or your local computer’s sound system. End-points can be remote, they can be grouped and synchronized, or they call all play something different.
Setup is really easy … if all of your gear is on one network.
The most important thing to do if you decide to give Roon a trial is to explore it FULLY and not just think of it as a flashy music player application (as you’d be missing out on the best parts).