There is very little if any differnce. Weight difference is within grams, if that. Many (most ) mountain helmets have detachable visors. The "road" helmits are somewhat more elegant (I can't vouch for that either). The main difference is in demographics. One type of product marketed and targeted at TWO very different types of clientel. Mountain bike riders are more apt to up-grade to hi-tech items, performance enhancing items other things,a helmit though gear adds nothing toperformace in their realm and because most helmits are safe anyway,companies can only squeeze so much out of mountain bike cyclists. Roadies seem to hold aestetics in higher reguard, willing to spend more on a hemit than tires for example,relative, not equal to cost of course . Funtionally the two "types" are identical. So in the final analysis, I'd say the OP is 100 % correct in his evaluation.