I haven't been able to access all the links above, but generally, my view of tapping is that it is a useful device, but it is very limited, as Nigel points out above--You can't base a whole repertoire on it, because after a few minutes, you've used up all the tricks--and listener interest wanes quickly--

There really is no option for playing sustained notes, and, because the technique is very staccato, harmonies can't be developed very much. Players often stick to one tempo, and that can be the kiss of death--Also, it is a very noisy technique--Stanley Jordan's string noise often came close to the level of the music--

Flamenco guitarists do it, and make it work very well, but they use it sparingly--