And you are yet to present a single upside, if there is even one.

This is a flippant statement, honestly, as it disregards the premise of the discussion. It's memory safety. That's the upside. The author even linked to memory safety bugs in OpenSSL. They might still exist elsewhere. (I realize there is a narrow class of memory bugs that C compilers understand, but it's just that, a narrow class). We have scant way of knowing whether or not they exist without significant testing effort that is not likely to happen. And it would be fighting a losing battle anyway, because someone is writing new C code to maintain these legacy systems.