Quills are much maligned - but they serve one useful purpose.
to cut the time down till con4 is available. if you have a low cost 1 air mage, it is well worth the time and gems to pump out 5-6 of these. Payback is on the order of 1-2 turns.
Payback in terms of investment of mage time vs RP gained from the Quill, sure. But I can't think of a single situation that I won't find myself in 20 turns with a dozen good uses for 25 Air gems that I don't have.