I’m not entirely sure. The clearer delineation (a lot of people get tripped up on .org vs .com, but it’s still clearER) of having the code published by a foundation might be of greater benefit to public than a pbllc, even just for marketing comms.
But automattic doesn’t have an obligation to continue to fund the charity foundation. Where as a pbllc does have a legal technical obligation to fulfill its mission statement.
I’ve definitely fallen to the simplistic analogy that at proto is like .org and bluesky is .com but it’s not quite as simple or clear as that, but at proto is mit license so its still similar.
I also think there is some technical distinction between wp.org which is just the code presented under a GPLv2 license and the foundation, I’m not quite sure if that’s a business formation distinction or not.