My gf is using the 16-50 as a 16/3.5 and guess what? It's perfectly fine. It's featherweight, cost 15$ when bought with the body and image quality is fine. The alternative is the much more expensive 16/1.4 which is also a much larger lens.
Power zoom is probably there to keep the lens even more compact, they are probably using it to collapse the lens when it's powered off.
This is an even smaller kit lens with a slightly larger field of view and I'd be happy to get one with the body. It's a great starter lens and works just fine as a cheap wide angle.
Size comparison ... 15-45mm vs 16-50mm vs 18-55mm
Another size comparison - 15-45mm vs Pana 12-32mm vs Sony 16-50mm
It's quite small indeed. I really really like the fact it starts at 15mm.
Klaus, are you going to review it at some point?