Magical workers of the world unite! THE REVOLUTION HAS BEGUN!!
Although seriously it seems like rather then gig economy it'd have made way more sense there for the fairy kingdom to just flat out hire her full time, and/or negotiate with the regular government. The MG series Asuka and kind of Nanoha are the only ones that come to mind which got this right. If there really was some sort of dark evil invasion that threatened the world, of course any real government would want to support efforts to fight it. Assuming conventional weapons are either fully ineffective or just can't handle everything, they'd in turn be very interested in supporting any of the limited numbers of magical super soldiers they could manage and offer them significant support and benefits to stay on side. I guess in some cases it's understandable that certain people would want to try to hang onto their regular lives if it was possible, particularly as kids. And the temptation of magic power could make governments and militaries really nasty too.
Also I wonder if the ability to go truly undetected is in retrospect going to look like a temporary historical artifact of the 80s/90s/00s. Something fun and cute, but increasingly hard to accept in a modern setting. Even with recognition inhibition magic, these days the kinds of tracking and surveillance assets nation-states have available are increasingly extensive. Just ducking into an alley is probably already useless once government is actually looking.
Edit: unless of course government itself helps, and that might be a big benefit they offer, a magical girl version of witness protection programs or what they do for covert assets. Of course, certain powers, like any strongish version of time/space stuff, could make it still possible. But those tend to be very rare not ubiquitous.