Personally, I would always prefer the gable roof option: not only for the reasons already mentioned here, but also, for example, because of the possibility of an open gable. Furthermore, a gable roof is always more modern – well, if you like country house style, a hip roof is preferable. However, one has to weigh how to accommodate a possible later expansion for a children's room.
I feel that a bungalow with a gable roof is architecturally downgraded to a barrack. A kind of fair beer, so to speak. I see it the opposite way regarding gable roofs being "more modern"; I find them more conservative.
However, you are right about the expansion: A hip roof means practically sloping roofs on all sides, without dormers, so only flat windows; with a gable, you can also have facade windows – climatically in my opinion a relief. Also, in addition to knee walls, you then have actual straight walls.
What is an Abschleppung?
An Abschleppung is when the roof is extended further at one point, almost like the hat being pulled lower over the face at that spot. The advantage is to avoid distortion in the clear roof shape that otherwise occurs with protrusions in the floor plan (as here caused by the entrance porch). Visually, it just calms the roof surface; structurally, it saves the roof frame from having to adopt a more complicated geometry at such points.