This is one thing I've never understood about certain types of weight-weenie cyclists. They'll brag for hours about how light their carbon-everything dream machine is, and tell me how much weight I could save by not using my handlebar bag or Carradice. Then they'll stuff 2 tubes, 3 CO2's, an inflator, levers, 3 Clif Bars, 3 gels, a tube of NUUN, 2 bananas, some sunscreen and packs of Chamois Butt'r into their jersey pockets and now their shirt hangs halfway to the bottom of their shorts.
Weight is weight, whether you carry it on the bike or on yourself, you've still gotta lug it up the hills just the same.
I can see if you carry a courier bag and put everything in it, then there's no additional pull on your clothing. All I ever carry in my jersey pockets (left to right) is garbage (wrappers and pages of cue sheets), spare water bottle, and a bandana I use to mop my brow.