This will be one of the last times the old GT8-100C/2S TramTrains are used. They can be driven from both ends, and such are used for shuttle services like this, where normal turning loops are not available. Starting next year, the remaining C/2S services will instead be served by the new class 492 TramTrains.
Yeah, that surprised me too, I had assumed that all trams like this have a driver’s seat on both ends. (Pretty much the only thing I see here in the U.S. though is the Siemens S70, so I don’t see many different models.)
Is the advantage simply cost and more passenger seating?
Well, on true one-sided trams you also save the equipment for an entire driver’s stand. Although that (mostly) doesn’t apply here.