This is a central concept in Roon: don't use the folder/directory structure for navigating your library, use the metadata features. Below is something I wrote in a separate thread (and others dating back to 2015).
Many of us (and the Roon team) resist the folder concept and this is part of a prevailing trend in the computer industry for managing all kinds of content. You see this in many other systems.
We observed that it is easier to find things in the global internet than on our own computers. In the case of music, a search on Amazon is much easier and quicker than navigating your own folders in Windows. And as search became more widespread, we abandoned folders. For example, mail systems like Outlook have folders but few use them anymore, we use search instead. And for common lookups, we use "smart folders" or bookmarks as a way to pre-package searches.
Some of us also object to having to act as librarians, carefully filing things away in the right folder.
But it isn't just that folders are inconvenient, they are actively harmful. The main problem is that an item can be in only one folder, and once you put it there it is difficult to find it under a different perspective. I recently downloaded a recording of Beethoven sonatas produced by Audio High, and I might want to put it in a Classical folder, or in a Piano Sonatas folder (which may or may not be a subfolder of Classical, there are avant-garde sonatas), or I may file it under Beethoven or Ludwig van Beethoven or under the artist Robert Silverman, or under MQA, or under Special Downloads or even under Audio High (good to keep track of where I bought it in case the file is lost or damaged and I need to log in and get a fresh copy), or under Recent, or under 2016/November/12. Which is right?
What we need is a "polyarchy" where an item can be classified in multiple ways and looked up equally easily under each. The album sits somewhere on disk, but all those perspectives in the polyarchy are available to you. This is what Roon aims to do. And it largely achieves it, although there are some rough edges that are being sandpapered.
This is why you see resistance to the folder concept. It isn't just inconvenient, it is harmful.
That said, you need some reasonable directory structure for when you want to copy albums to another device, or similar stuff in the operating system. But this structure is less important (the operating system also supports search!).