Earlier quoted context omitted.
Speaking as an American, this is a part of American culture that's so weird -- using a pre-made mix as a base for a recipe that it's not designed for. That recipe looks like it just has flour, cocoa powder, baking powder, and salt pre-mixed (with a load of other garbage you probably don't need). People don't seem to realize that you can just buy those ingredients yourself. It doesn't take that much extra time to meas…
I bet you couldn't consistently make a cake even half as good as a box mix for even triple it's cost. People who don't bake often then baking is just throwing some stuff together and heating it up. It's very hard to get consistent results! It's literally an exact science. Did you weigh all the ingredients exactly? Did your mix and sift them evenly? Is your leavening agent fresh? Did you account for the humidity in yo…
Box mixes use powdered milks. Powdered vanilla flavor. They use the cheapest powdered chocolate. Sometimes they don't even both making you throw in an egg because they use powdered egg.
I don't care how precisely that's measured, it's not going to be as good as my recipe with fresh eggs, fresh milk, real vanilla, and good quality bars of baking chocolate.
And that's even setting aside techniques. My favorite chocolate cake involves pouring boiling water into the ingredients, because of the way it melts the chocolate. Show me a Betty Crocker mix that does that.
Obviously if the only recipe you've seen from scratch is just a replica of the things in the box (and you use similarly low-quality ingredients) then sure, having the precise measurements is nice, I guess.