The benefit is small, but there is a difference. The lack of moisture in the nitrogen also protects the inside of your rims from corrosion.I say snake oil but who knows. I like to keep things pretty simple with my car.
As long as they do it for free than you should be happy. Even if they fill it with nitrogen it doesnt mean that you always have to use nitrogen. You can mix regular air with nitrogen but it wont give you any of the gains as just having nitrogen in your tires.Have yet to fill them up and no plans on doing it. I suspect the dealership will probably do it one day when I least suspect it...sneaky so and so's.
Theres an article I posted up top that talks about the whole subject. Read through it and you'll get a good understanding of how the whole nitrogen thing really works.i have not filled the tires with nitrogen. what is advantages and disadvantages?
Here's a pretty informative article about the truths and myths about putting nitrogen in your tires. Any questions you have should be answered in the article.
The Truth About Filling Your Tires with Nitrogen | The Truth About Cars