The body language here tells Loki this is a spur of the moment suggestion, not a wily plan come to fruition, but either way, it's clever. He approves of spontaneous use of new information to maneuver one's way out of trouble just as much as he does of elaborate gambits, and the look on his face is one of surprise, with delight following hard on its heels.

It's almost flattery in itself, to witness. "...I'm starting to quite like you." He says. "Nicely done."

If he had a plan for what kind of favor he actually wanted from Viatorus, he wouldn't cotton to this solution quite so well, but since he doesn't and was merely hoarding favors, and since it sounds like he's going to get at least some attempt at mischief-based worship, he's happy to give him this one.

"Yes, that's a deal. I will meet your wife in good faith, and you will introduce me to your priests in good faith, and we will call ourselves even." He offers a handshake.