Agreed on what has been mentioned already, just adding my $0.02. By twisting 2-3 strands, you do create a "larger" (in diameter) wire. Taking 2 strands of 30g twisted wire gives you about a "single" 28g wire. In addition, due to the gaps created by the spacing between the twisted strands, and the spacing of the wraps themselves, you do create more surface area, that the juice touches. More surface area, more vapor, more cloud, more flavor.