I said I'd use it to get good items and weapons because you don't always know where those good items and weapons are.

Example. FFIV Advance. i wouldn't have known about Eblan Castle or the goodies in it without a guide. I suppose I could have wasted my time flying around the entire world looking for things that might be useful, but I just don't think that's a productive use of my time.

And it's no different than trying to get 100% at all. They're both things you have no way of knowing on your own. You either waste your time or you be smart and find out where the good stuff is and then go get it.