The split and relaxed shoulders are amazing. I really wish more tech would try this approach. The Wii controller (Wiimote + Nunchuck) was my favorite controller for this reason and I have yet to find anything as ergonomic.
You can do the same thing with the Nintendo Switch controllers. It's my favourite way to play.
Yes! I always use the Joycons like this. Just rest them however I'm comfortable. Although the rectangular shape makes them uncomfortable to hold in the hand for too long which is a shame.