I've had guides for pretty much every game that I can get them for. Unfortunately, it seems to be a dying market (I've tried to find guides for certain other games, without success), I'm guessing primarily due to the rise of free internet guides and videos. There are also a lot fewer guide makers than there used to be (I think it might be down to just Prima now in the US--they merged with Bradygames fairly recently, and other guide creators like Nintendo Power disappeared some time ago).
I like the guides because I like reading them. The issue I have with a lot of modern guides is that they tend to be more minimalist than they used to, and the writing style isn't as entertaining. I tend to use the internet for most of my quick Pokemon-related searches, but there are times when it helps to have a physical guide (and I'll admit that I did dig out my Versus Books RBY guide for planning out teams for the re-releases).
My first guide was for RBY, made by a manufacturer whose name I can't recall. It's not a company I ever heard of again. It also included a Pokemon Snap section, with tips for getting a perfect Mew photo.
My favorite guides are the Versus Books ones (for RBY, G/S, and Crystal). My first one was the Crystal one, and I learned all about egg moves, breeding, stats, and more from that book. Even though it had a fair number of typos, and even though those books have some strange ideas about strategy by modern standards, they got me started thinking about competitive Pokemon battling in the days when my dial-up internet was far too slow to turn to for rapid-access information. (Plus, if I was trying to play when my parents thought I should be sleeping, waking up the house with the sounds of dialing in and the "You've got mail!" announcement wasn't too practical.)