What a great question! I'll try to stay on topic as much as possible, but you have me thinking about all kinds of interesting tangents now.
The first thing I have to ask is:
Aren't ALL decks just pretty pictures? It's not the deck itself that is divinitory, it's the connection a person has with it. Certain artwork and certain methods work better for different invididuals. And YES, there are people who can do very good readings with sticks and rocks. I even know a woman who can give very accurate readings from the leftovers on your dinner plate. See, it's not the food, it's HER. Most of us aren't that skilled, and need a gimmick to fuel our intuition.
With that in mind, the Faeries Oracle is quite powerful for many people *because* it is less stuffy and more playful than 'proper' decks -- just as you said! This makes it easier to let down your guard and just run with it. So you don't worry so much about memorizing official meanings, or doing things the 'right' way. Isn't that the advice experienced readers give newbies on how to learn?
You wouldn't know it without having the deck and the book, but there is also a surprisingly well-thought out hierarchy of cards, almost akin to the suits in normal decks. Each card is in the deck for a specific reason, and not just for its looks. They are beautiful, cute, silly, haunting... and there are many things going on even in the simplest card. I've had my deck for about 6 months now and use them quite often, and as I was sorting the cards out last night I happened up a teeny tiny little guy in the corner of a card that I had never noticed before. I marveled at the details and nuances that aren't always seen right away.
I didn't give much thought to fairies or Froud or anything related before, and I've found this deck powerful BECAUSE it is playful. It works much better for me than any of my tarot decks. (An interesting twist is that I'm now feeling more confident to hone my skills with my other decks.) With my psychology background, I understand that when people have conversations with their faeries, it's probably accessing different parts of your own psyche and not a living, breathing, flying fairy. BUT... as I said, I believe all divination systems are tricks to access your own psyche, spirit guides, angels, God, the Universal Energy, or however you interpret the source of psychic energy.
So, yeah it's silly, and that's why it works. Now I'm off to go research the Vertigo deck. LOL!
LR