I think it is nice that they made such a thingy.
However, unless - as J. Patric said - they are to be used with film that's only available in 35 mm, i too don't think these thingies make much sense.
That same nice portrait could be had by cropping the 6x6 the Rollei normally produces. No need to have to expose a full roll of 35 mm just because for one shot cropping to a smaller format would create a nice angle of view for a portrait.
Even the 35 mm adapters that make use of the full width of the camera's film gate don't make much sense to me.
Still, nice that they made it.
Better to have an option and not need it than not have the option at all. That thought may sound silly, but it has other virtues. It's that thingy we call "luxury", and somehow we all appreciate it.