You ignored my first point. You can trust the self signed certificate to be used by the same entity(A or C) after the first connection, admittedly you may have been MITM (by C) for that first time(and renewal times) and because of that you may be screwed. Alternatively if you are trusting other entities(B) to verify the certificate of A while B are not trustworthy then after that first communication (even if that first communication was legitimate) another entity (C) can pretend to be A and so long as B verifies C then you are in trouble. I am pointing out that they are different risks and I agree that in nearly all use cases it is better to use verified certificates than self-signed for general internet use, that doesn't mean that there isn't a reason to do otherwise though.