Do they tech you how to have more range or just help you hit notes better?
I personally too voice lessons for two years and my teacher really stressed things such as using your diaphram when you sing, breathing correctly, and staying on key. Being critiqued by a professional and learning their techniques can be very important if you're serious about improving your singing voice.
They teach you how to breathe properly, how to hit higher notes, how to sing properly without damaging your throat...the list goes on and on, really :P
i would think that it would help you in all areas.......