It may depend. When I see a cyclist having lights on their helmet, it looks like a light from some poles in distance, unconnceted to the rider. On the other hand, when I have rear lights mounted on the lower part of the seatstays or the legs of the rear rack, they lighten the ground and produce a large (flashing) red area on the road that follows the bike; I suppose that helps with visibility (provided there is a taillight in higher position, too).
Canklecat ( whom you quoted ) had it right. The higher mount of the light helps the cyclist get seen when in heavy traffic. That said it also makes good sense to use a second light mounted either on the seatpost or on some other part of the bike at the same height.
Any ( steady ) light emitting source viewed from a distance at night will seem "disconnected" unless the person using it is also clad in lots of Hi-vis clothing or has the lamps using typical "flash patterns" that are usually associated with bike use.
IMO it's not that important that you can identify the light source with a type of user when viewed at distance. What is important is that the light is seen and the viewer knows that whatever is producing the light is something that he/she does not want to run into. I figure that's only common sense. Of course it helps if the light also emits a "bike related" flash pattern because that WILL help alert the approaching driver that "there is a bike somewhere ahead".
Case in point; I had a car come up beside me on a night road ride last year and the guy driving the car winds down his window and tells me he could see my rear light a half mile away. At the time I was using a very bright 200 lumen Xeccon single emitter red flashing light on the seat post. The guy told me from a distance he thought I was an ambulance on the side of the road. I figure it's not important what he thought I was at distance. I got seen and no one is going to ( knowingly ) run into something that looks like an ambulance.
