Drawing up schematics is just like writing code.
You can write code that is functional and technically correct... but without good structure, layout, indentation, commenting, documentation, sensible names of variables and functions etc. it is a pain in the arse if you have to take somebody else's code and work on it and maintain it.
Drawing up schematics is exactly the same. You can have a technically correct, working schematic which is a pain in the arse to read and follow and debug, if the layout is not tidy and neat and well documented.