Given everything David does for the Perl community, particularly (in this context) all the toolchain related things, it's hard to think of a better thing to spend 'our' money on.
TL;DR: yes please!
David's behind-the-scenes work on the toolchain has been incredibly valuable, as has his help and advice. Getting him in the same room as other core toolchain workers for a few more days would be invaluable, so as Neil says, there are few better things I can think of for spending TPF's money on.
David's attendance at past QA hackathons has always been a positive thing for the Perl community. Strongly endorse this grant application.
+1 - I look forward to collaborating with David in Lyon!
+1; it's definitely worth our while to get David to the QAH