Ttwo weeks ago i flew SAS Domestic from ARN to GOT and back.
Totally paperless (first time for me)
About 12 hours before dep I got a SMS asking me to check in. I checked in over the internet with my phone and received a boarding card picture.
At the gate held my phone over the reader and went on board. No ticket, no boarding pass and no talking to check in or gate staff.
The phone boarding pass also got me through security, where they have the same readers as at the gate.