On the list of horrible things in this world, mornings land in third place, behind scabies and Martin Shkreli. You have to wake up. And unless you work from home or are an aerobics teacher at a nudist resort, you have to put on pants. And most people have to drive or take public transportation.
Whether you're gripping the steering wheel or gripping the subway or bus pole, chances are you only have one free hand (at least) to hold on to something delicious and/or nutritious for breakfast. Sure, you could just wake up early and eat something before you leave the house, but then what would you do during that obligatory commute? If you are going to spend extended time sitting in traffic or on a train/bus, you might as well multitask.