The problem is then you still have to go there and pretend to work - sitting in front of a screen for 8 hours while doing nothing probably sucks the life right out of you.

I mean my job is a little bit like that. I have automated a lot of annoying stuff with VBA (but have yet to start with python, it's on my todo list). However, it's impossible to automate everything - so in the end a worker is necessary (but not the hours that were planned). I would assume it's the same for many white collar jobs. [since I'm paid by the hour the automatization is not really worth it monetarily by itself, but that's another discussion]

Another aspect regarding agency and happiness: I've noticed that I have some (kind of stupid/gameified) sense of accomplishment when I sort my mails, write down the current status of a project or something similarly "boring" but important stuff for ease of mind (similar to doing a todo-list to become organized). Just knowing (and accomplishing) that everything is in order is quite satisfying.

That’s the business proposition for lots of businesses, I don’t see why it’s invalid if an employee can figure it out.

You certainly wouldn't be the first one to do it!