Yes, it will absolutely benefit AS in the long fun, and in fact in the short run too.

Because Vanilla has allowed the feedback loop to be shortened, we've been able to fix more than a dozen bugs in various areas that afflict ActivePerl as well, in places like CPAN.pm, Term::ReadLine, Win32API::Registry and others.

There are not bugs in C code related, they are bugs in Perl code. In fact, in some cases, I cannot see how the module could possibly build AT ALL so that it could be bundled into AP.

The VAST majority of bugs encountered so far have nothing to do with compilers at all. They are ordinary bugs in ordinary code. But perhaps because they are bundled, or perhaps because the feedback loop is at 6 month intervals, they aren't getting fixed.