My opinions...
First off, I think Ayeka's doing a good thing. From what I read (I haven't actually hired her for anything yet), she does all the work of getting a coffer key, and for a good price. And I mean -all- the work. She gets the party set up, she finds the camp, etc. You just sit back and watch the fireworks.
Let me do a comparison. Ever get delivery pizza? You could have bought a frozen pizza, or made your own, for a fraction of the price. But you paid for the convenience. They mix the dough, they put the toppings on, they cook it, they clean up the kitchen, they even bring it to your house. That's what you're paying for.
I also think Phraust is doing a good thing. He's offering to help with coffer keys. Key word, though, is help. You still have to get the party set up, you still have to find a tank, a healer, enough DDs, etc. He just helps a bit and lends his TH2.
What I -don't- think is good, however, is the way it looks like Phraust is attacking Ayeka. Twice a post of his offering to help with coffer keys for free showed up right after Ayeka offered to merc for keys. The first time was either coincidence or due to the intervention of another poster, however, as Phraust's topic was bumped by Osuka a few months after it had died off. The second topic was a very strange coincidence with an ambiguous flame directed at no one in particular, but it was posted right after Ayeka's last mercing topic was made (about 40 minutes after, which imo is too long for Phraust to not notice Ayeka's topic until after his was made, which is what he's claiming). Not sure if I believe Phraust, but if he's lying about that, then I've really lost a lot of respect for him...