Wetsuits do make you more buoyant, keeping your legs and hips higher in the water and thus making you faster. They also can keep you warm in cold water. Though I must caution as a seasoned cold water swimmer (who doesn't wear a wetsuit), your feet will feel like they are burning if you have never swum in cold water before. That being said the sensation usually subsides in a minute or two and then your feet get aclimated.
Although I'm glad that wetsuits are here making open water swimming accessible to all. I still dream of a world when more people who swim in open water would go naked (i.e. without a wetsuit). But that's just me :)