I have played around a little bit with sidecar but I have to admit that, as with many iPad features, I am not sure I fully understand the purpose, the added value and, in fact, which functionalities it brings to the table.

Do you use Sidecar routinely? For what do you find it particularly useful? Are you missing something?

Edit: This is a note mainly for me. In Mac OS, Spaces do not work as one would expect. In fact, there seems to be no support for virtual desktops under Mac OS and Spaces appears to be a half backed attempt at implementing virtual desktops through Mission Control. Mission Control lacks three crucial capabilities: 1) the capability of having two or more full screen windows in a space or virtual desktop; 2) the capability of cycling between the (possibly full screen) windows of a space and, finally, the capability of moving a full screen window to a specific space. Because of these deficiencies, one cannot work with spaces as one can do in Linux with virtual desktops. While the need of using multiple screens for many tasks is genuine and unrelated to the usage of virtual desktops, it seems clear that, in a system in which virtual desktops do not work as they should, there is likely to be more need for more and more screen real estate. Thanks to all who contributed to this thread, I was under the impression that Spaces would work like Linux virtual desktops and I have learned that sadly this is not the case.