Audio streamers have the following
1) Music subscription service
2) Free radio
3) Local music on NAS/USB stick etc.
4) Cloud music (access your music on your NAS anywhere in the world)
I don't use roon as it's something like £800 and you need roon certified products, and a PC/Intel NAS.
If you have a NAS it'll have a service which scans your music and video files. Any audio streamer/video streamer can then connect to that and play audio/video either through TV interface or app control
My system is a Raspberry Pi5
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with picoreplayer installed
www.picoreplayer.org
Configure it, tell it where your local music is, let it do it's scanning
When the Pi5 boots up, my audio streamers connect to the Pi5 service, and in Windows you see this
en.wikipedia.org
And on a tablet you see this (Material skin)
https://pinkfishmedia.net/forum/proxy.php?image=https%3A%2F%2Fi.postimg.cc%2F7hXYYQfX%2Fkensal.png&hash=aa4aaa6ad654af017623b345d9637272
Then entire local music is able to selected from phone/tablet/PC, to each streamer, or to any PC/AVR/TV
LMS reads in coverart, saves them to the database, retrieves lyric info, band info etc
Other music scanners do this, some less, some more. Roon I believe integrates local music and subscription service, so as I understand it if you search for "Blondie" it'll show your own albums plus ones that are streaming from various stations.
Wiims support UPNP/DNLA and LMS/softsqueeze so you can use LMS- or other servers like minimserver etc.