To me, walkthroughs are for those moments where I don't really have the time to do trial and error experiments. Going blindly and figuring out what to do is fun and challenging but there's some points where if I don't use a walkthrough, I'm gonna be doing that stuff for one hell of a long time. With plenty of games to play and things to do outside the virtual world, I can't afford to stay in one part of the game for a very long time.
Plus, there's nothing wrong with using a walkthrough. It can help you backtrack and get things you've missed while progressing along the game, especially those notorious "missed the item? too bad, it's gone forever" items. I avoid walkthroughs whenever possible but I know for a fact when it comes to stuff like pieces of hearts or sidequests, I will use a walkthrough because it saves me the pain of having to try and find them, only to end up failing.