As I suggested before, the "magic gate" should dispense a timed & zoned seat check/receipt, which you would insert into the little tab thingy in front of you if sitting, instead of the conductor doing it for you, or flash it as the conductor walks past if standing. So that is another minor time saver. I'm assuming anybody traveling inbound or from some other station like Yawkey would see no change.
If you show up a minute before departure & need a ticket, buying the ticket on board would no longer be an option so you would miss the train under this new scheme. So I guess I'm screwed
These fare gates could take media that conductors don't accept, like charlie cards, charlie tickets, credit cards, a Mobil Speedpass, Apple Pay, Google Pay, PayPal, even other transit agency cards. Unmanned stations would get similar machines, with conductors only having to issue tickets at the smallest or most vandalized stations.