Not OP but yes. You configure your desired output format as well as a number of other options like stripping subtitles etc.. and just let it rip. It's saved me terabytes of space with my collection.
I use Radarr and Sonarr containers with the Sickbeard MP4 Automator built in, and run some post-processing scripts in both Radarr and Sonarr to get everything in M4V (Apple household).
It can. I'm actually using it to transcode from h.264 to h.265. But yes, you can also transcode to different formats, codecs, audio etc. I just started using it, but It seems pretty flexible and extensible
Yep exactly like the other commenter said :) I don't have a discreet GPU in my server, and I didn't want it using CPU to transcode, so I set up a node on my gaming machine. So the server queues up files and the GPU in my PC transcodes them. Blew my mind when I got it working