Usually I'd be against lazyness, but this is a pretty good timesaving idea.
Making muffins always makes a powdery mess, then a goopy mess and dirties a mixing bowl & spoon. This way, all the mess is contained into one small jug that just gets thrown away at the end. You couldn't ask for less hassle. I would say it's the best for whipping up a breakfast of champs. Preparing muffin batter while working on other things could be a time consuming hassle. I think I'd much rather the shake 'n' pour routine....since I'm a lot better than you, you should do the same.