I'm 85% sure that they're not self-service yet. They've been testing that, but I think all of the gates are still using manual scanning via CMs.
Eventually, I believe the screen will work sorta like the TSA booths at a lot of airports (inc. LAX) to compare pictures against the one in the system and/or take a picture if the ticket is new. The whole thing should theoretically be faster than having a CM switch between features in their device.
The tech between WDW and DLR is vastly different. WDW is entirely RFID media across the resort, from hotels to parks, so everything can be tied together.
DLR doesn't have user accounts like WDW does - instead of everything being based on a user account like at WDW, DLR is based on the ticket barcode, which makes what you're describing impossible. At WDW, they can just scan a new card and attach it to a person, and the system knows what admission they have. That's not possible at DLR. The only real identifying mark of the user at DLR is the photograph on the ticket.
Even to implement MB+, they used the DL app as a bridge between the ticket barcode and the RFID in the band. (At WDW, the MB+ is attached to the user account.) Compared to that MMSSHP ticket example - you have to manually switch the MB+ to an OBB ticket to be able to use it. Any physical media at DLR would be specific to the ticket, so you'd have to get one for admission and a separate one for the OBB ticket.
I keep hearing mumbling that the phasing out of physical media at DLR is partially cost - tickets are almost entirely sold digitally now - but there's seemingly some issue with them printing existing barcodes, they may have to re-issue an existing ticket under the new barcode on the physical media. (It sounds like they may not be able to print the existing barcode onto a card, but I'm not sure about that.)
Great info! I guess it makes sense - the tech at DLR historically has lagged WDW. WDW switched to stored media tickets and began experiencing with biometrics (finger) in the mid-90s with AP. (Eliminating photos). DLR was still stamping tickets and issuing photo based AP until 2002.