I’ll give you an example on how I use the sidebars in Obsidian. On the left I usually put stuff that concern my whole vault. Stuff like favorites, recents and sets in Anytype are a good example. But on the right, I like to put things that concern the current object. Things like backlinks, outgoing links, outline of the object and many more advanced features.
Currently it makes no sense to implement this, but it would make a lot more sense with the new sidebar design that will use widgets.
Also, the right sidebar might be useful as a second pane/panel. Apps like Logseq and maybe Roam used it like that.
Here are some more examples of widgets that might be useful: