Put yourself in my shoes. You'd been a member for years, almost 3000 posts, hundreds of thousands of points of hard-earned reputation. Your account has got you work. It's something you value.
Then some scrot hacks your account. Clicks delete. Everything gone. How would you feel?
So instead, there's a process. You talk to a real person. They work out if you're really who you say you are, and instigate a deferred deletion. That gives your account 24 hours with a banner over the top, allowing you to cancel the deletion request.
This provides some protection from hackers, some protection against impulse. I can understand your misgivings —given your expressed intentions— but it's a feature and one I'm very happy exists.
If I were you, I'd get your request in, log out and forget about it.
There's nothing else you need to do to stop being part of the site.