Because when it is to actually get paid work done, all the bloat adds up and that 3 days upfront could shave weeks/months of your yearly tasks. XKCD has a topic abut how much time you can spend on a problem before effort outweighs productivity gains. If the tasks are daily or hourly you can actually spend a lot of time automating for payback

And note this is one instance of task, imagine a team of people all using your code to do the task, and you get a quicker ROI or you can multiply dev time by people