I suppose it's an admission of defeat to buy a game guide. But actually I like them for the pictures as much as anything. And sometimes they are useful because they let you know that something is possible, rather than telling you how to do it.
My official guide for the Zelda: Breath of the Wild arrived today and I really like it. Lots of detail and lavishly illustrated. If you've got the game I reckon you'll get a lot out of this guide, whether you need it or not.