yes the map inside is nice. Honestly there are times where I had to read the strategy guide to make sure I was doing something right when encountering nasty bugs. I am talking about bugs with reviving dragons that are essential that you cannot kill..yes... it was a pain. I ended up reading what to do and found that there were two ways to finish that quest and that I didn't have to wait for the guard to do something about it and when I intervened and did it myself the bug didn't happen. So yeah, it does help.
I think I've only ever bought game guides for Morrowind, Oblivion, and Skyrim. I don't buy the guides for quest descriptions/walkthroughs. I mainly buy them to get a list of items, spells, skills, races, and classes (well, now its archetypes). I just like looking it over while in bed and thinking of different builds or gear collections I can implement. For that reason I think the guides are well worth it.
To be honest, in the olden days, a game manual would give you all this. And it could be that the morrowind one did and I am confusing the actual game manual for a guide. So I guess I got the guide so that I could get a proper manual. I usually only refer to the first 80 or so pages of the guide.