For consistency with Parrot itself, and Rakudo. I had a horrible misconception about this for a while.
POSIX has a special memory hack which conflicted with our symbol scraper.
I beleive this to be the last critical piece for Rakudo work.
It's completely wrong in several ways, but it works, and I don't know of a less wrong way to make it happen.
We're only implementing the string form; namespace considerations seem to imply parse_name is unimplementable for Perl 5. It will probably be gone in my PDD-31 replacement draft.