good question ;) ääähm...

its because my prior lightsets sometimes overrid the speculars, i just wasn´t able to find them... the ibl with contrast 1 or 0.5 had eaten it! or something else of the thousand things i am able to mess up did ;)
so i seperatet them to put them where i wanted for testing purpose. no deeper artistic sense, sometimes i find it looks nice. but thats the final realism death blow... call it stupid testing ;)