Along side your training, I'd be inclined to agree that they are somewhat useless/detrimental..
Prior to your training, I would say it could give you a good head start with muscle memory for effects of controls as well as building a general awareness of the cockpit / flying environment.
It certainly gave me a good head start when I started my training and, having recently taken an avid flight simmer up in the back of the RV8 I was amazed at his standard of flying - I got to be a passenger up front for most of the flight!
I'm a fixed wing pilot, however a few years ago I was given a trial flight in an R22 as a Birthday present. I spent many hours prior in FSX trying to hover, knowing full well that it would likely feel nothing like the real thing. I was hoping that at the very least it would allow me to get to the stage where I knew which input was the correct response to what I saw out of the window without having to 'think' about it. To my, and my instructors surprise as a result I was just able to hover - it wasn't the prettiest, but equally the instructor wasn't having to take control. Not bad for a first lesson!
In that sense I'm somewhat of an advocate for flight sims (it's also the day job!), however I'd also agree that they have their time and place and are far from a perfect instructional aid when playing on a traditional PC configuration - Charles is absolutely right in that it will teach you bad habits - overly relying on instruments instead of looking out of the window is a big issue. They will also do nothing to help you develop the skills of actually landing an aircraft. This isn't the end of the world prior to training but as Genghis says could start to have an adverse effect if you start trying to learn on both the sim and in real life in parallel.
VR does change this some what however - it still won't feel perfect, but the cues are much more convincing - plus the resolution is so bad you can't read the instruments even if you wanted to