You're both forgetting that the merchant was only pretending to be devout to the church and loyal to the central governments. In particular because they knew she has close ties to the church. She's using the convents to educate the masses, causing a mini-Renaissance. The merchants pretend to be loyal because it ingratiates them with the zealots who don't know better (i.e. not other merchants, and not the royals).

That's what his whole line about the motto of the Alliance, to be beyond human and be a profit seeking monster first, human second. That's what makes their line about how the two of them have so much in common is funny. They're both monsters first (one literal and one figuratively), pretending to be human.

Also, do not forget that she is giving them exclusive access to the gimbaled mariner's compass as well. Part of that was simply to have this meeting, but it is also a condition of their agreement. He brought mercenaries because he was afraid she was laying a trap for them. Her repeated insanely one-sided offers made them extremely suspicious.