If you can get around the trancoding issues (and some NAS's are doing a better job), its still very viable. I don't even do hardware transcoding on mine anymore (its a PITA to exposed quicksync to a VM) but it still does the trick for managing my library and watching broadcast.
Occasionally when my antenna gets a bad signal,namely on my local PBS, i can then stream it. But the point is I don't HAVE to. For the kids....95% of their content is PBS OTA recordings via plex.
I don't really use any of their features they have added, but am a lifetime plexpass and do share with some friends (who return the favor). I dont really stream from them, but i occasionally browse to see what may interest me. Which is very cool even still, like looking at what my buddy's netflix or prim recs are.