That article was interesting as fuck, but ultimately it's all about a new language-compiler-runtime model that provides safety, not security, basically a more efficient .NET. It probably does make implementing security easier, there's a section about how to implement capabilities in an object-oriented way, but I don't think it's the biggest obstacle right now.
We can already implement permissions checking in both plain old machine code and .NET, we just don't do it enough.
Historically, a huge percentage of security exploits occur as a direct result of violating safety. Not all, of course, but it's a significant enough proportion that it's simply not reasonable to treat the two as entirely distinct concepts.