I’m a practicing attorney using Obsidian. Right now, I admit that my most common use-case is with Daily Notes, to which I link the day’s call notes, a work log, and some thoughts. I’m not getting a great deal out of the PKM aspect yet, but I do have a “Legalkasten” that I’m building out for concepts, terms, statutes, cases, etc. Part of the problem with going outside the Lexis/Westlaw sphere is that caselaw isn’t static. That means that you can get yourself into trouble if you rely too much on your own database when you should be using the paid databases that include continuous cite-checking features.
Nonetheless, I hate having to take notes on caselaw inside these platforms because the UX simply isn’t very good. My compromise has been to download PDFs, load them into DEVONthink, and then just create links back to the online source for future cite-checking. Of course, as I gradually use Obsidian more and more, I’m hoping to continue to transition more to actual knowledge management rather than the digital file hoarding that I’ve historically done.