I'm not the expert on the bio but the gel has the advantage of being consumable while running.
Try drinking while running. Even at a slower pace it's hard not to spill. If you want the dosage correct you can't spill.
Well I assumed that during marathon you have places where you stop and drink. Usually there are even volunteers giving out water, you can have someone from your staff giving you a bottle of 1l of water-sugar.
But maybe I'm mistaken and they dont do that for marathon.
But maybe I'm mistaken and they dont do that for marathon.