I'm a big fan of SOPs and to-do lists, primarily because I have a pea-sized brain that's having a hard time remembering anything but the truly important things in life.
There is real value in the economy of movement in physical jobs. If you dance around with pounds of bricks in hand while trying to erect a wall, you'll exhaust yourself and make your labour less valuable, that should be pretty obvious with anyone who possesses half a brain.
There is equally real value in doing the same for non-physical repetitive tasks, like writing for this blog and then posting it online. It's easy to dismiss the effort of building systems as unimportant when it should in fact be the first thing to be designed upon the creation of a new repetitive task.
First, it's the mark of a professional to have work methods that are effective and replicable consistently. It saves everyone's time, even though it may appear occasionally to be very time-consuming, at least initially.
Second, if you have employee roles that cannot be easily overtaken by colleagues instantly, having the standard operating procedures written down allows you to train a replacement much faster and have them be operational in short order, instead of leaving them (or you) to figure out what to do on while the situation is already less-than-ideal.
In architecture and design firms, it's fairly easy to replace a designer who's sick or quits suddenly. At worst, the workload can be spread among the remaining designers while a replacement is found.
However, for very small firms and specialists roles, like a marketing person or a bookkeeper, it's much more challenging as there is usually only one or two in most offices, so when they quit, replacing them is exponentially more difficult.
Systems work to reduce that pain by making it easier to fulfill some of those functions even without training or experience.
Do you have a solid marketing system in place? What would happen to you if your employee in charge of marketing quit their job tomorrow?