I found that having cookies actively deleted like that often crashes websites inadvertently and it ended up being a pain to manage. Allowing a website to track you for a day or so is not the same as being tracked for months. I believe that it is not nearly as useful to marketers. Closing and reopening my browser after a heavy web session is not a big price for me to pay. I do it to free up resources on my machine anyway.
Sites I log in to I don't clear. Other sites _shouldn't_ be able to tell the difference between deleting cookies and being a fresh visitor. This brings a new problem, in the form of cookie and GDPR banners. But there's an extension for that, too: https://www.i-dont-care-about-cookies.eu/.
