The problem I see with a flat approach, I mean one significantly below 3 degrees, is that the "numbers" all are wrong.
Landing approaches are standardised as much as possible to help us fallible humans to put the aircraft in the "right place with the right energy state" repeatably. Hence we try to fly 3* as close as possible so that any variations are obvious and able to be seen and corrected. That's what the certification is based on too.
A flat approach is quite dangerous because the aircraft energy state is significantly changed - much more thrust to maintain speed and much less rate of descent - so a float is almost guaranteed, eating up runway at a truly alarming rate.
If Miserlou means PAPI, he is correct - it is a point source and you will end up at the same spot, but your energy state will be all over the place. With a wide body aircraft you may well rip the wire off the fence though because the wheels are so far below the pilots eye height.