Just to add...prediction of span-wise load distribution is also important for determining flight characteristics wrt to stability, for example overall pitching moment 'Cm'
Generally though, as mentioned, anything that reduces induced drag...ie increased aspect ratio or favorable overall load distribution, reduces the thrust required to overcome the induced drag, hence its relation to performance, although increased AR has to be balanced with the increase in weight and profile drag
It's helpful to remember that for an equilibrium flight condition, every time drag is increased there has to be a corresponding increase in thrust...whether discussing climb, cruise or turning performance...
