As far as the stem/bars positioning, I would expect the bike to have a most flighty steering response with such height and with such little offset from the sterer.

As for an extreme rearward saddle, this precludes the possibility of easily moving to a stand-and-lean-forward riding position, as might be needed for steeper inclines, and so increases the likelihood of knee strain and injury. So it's suitable only for relatively level ground.
Advantages are that it matches the handlebar positioning for an upright position that would suit riding in traffic. Also that it might improve climbing traction where an extremely slippery surface happened to exist. But again, unsuitable for steep climbing imo.