I made a few errors with this thread. Please see pwuille's corrections for more details on what I got wrong or view a revised version of my thread in a separate comment below.

Below is pwuille's response from reddit: https://www.reddit.com/r/Bitcoin/comments/12ofdk4/running_a_bip_324_bitcoin_node_can_help_make_you/jgip26u/

While the construction does have some properties of TLS, it's not based on it. The BIP explicitly goes into why TLS isn't used.

Depending on the interpretation of that term, maybe, but stating this outright is a bit misleading. Bitcoin nodes have no identities (as they don't trust any of their peers anyway), so the traditional concept of a man-in-the-middle doesn't apply. What BIP324 is raise the cost for wide-scale surveillance, by forcing any spy to actively intercept any connection, or run their own nodes, rather than being able to observe passively.

Now, in some cases nodes may connections that are deliberate rather than automatic, where the node operator wants to connect to specific other node. For example, you run two nodes and want them connected to each other. In that case, ideally, there does exist a means for ascertaining the connection isn't being man-in-the-middled. BIP324 has affordances for extensions that enable it (in form of a session id that can be compared out-of-band, or otherwise authenticated), but the functionality isn't actually part of the current spec as there is active research on that topic.

Definitely.

That's really premature at this point.

Source: am co-author of the BIP.