Browsers are being increasingly proactive in offering protections, which I think is a good thing.
Browsers that update themselves more transparently, not requiring user input or explicit permissions are going to I expect be updated more readily than the OS, particularly where updates to that often put-off by users.
And as the browser is going to be the primary source of someone trying to exploit those I suspect, then that is definitely a good place to have one of the layers of protection before we get proper fixes.