It's pointless. It was originally popularized by Duane Allman, who's first guitar was a Junior before he fell for '57 Goldtop, '59 Burst and SG LP guitars.
It doesn't create the sustain of a wraparound because it's not the guitar's bridge.
It doesn't do anything for tension which you couldn't match by raising the height of a regularly-strung tailpiece. This puts that particular "benefit" in the same field as "heavier strings = thicker sound". You have to compare it to the other method on the same, unaltered guitar to really hear the difference, otherwise you could compensate for the change with minor set-up tweaks.
It's mojo and it looks cool to certain LP players, but top-wrapping the tailpiece of a two-piece Gibson bridge setup has no benefits, tonal or otherwise. It also marks up the tailpiece if you do it long-term, and can cause metal burrs which could dig into the hand or scratch the arm in the future depending on how you play.
rps-10 wrote:Plus I've seen one (can't remember who) pro player who had the bottom 3 strings go back through then over the tail piece and then the lighter strings straight through. So a half and Half mix.
Zakk Wylde does that according to pics of his kit I've seen.