Well, think about it for a minute, who mostly influences the decision on the photographer on a wedding. Is it the bride or the groom??? The bride wants that light, airy look, while the groom might lean more toward the dark and gloomy. LOL All kidding aside it does remain a more popular look for the genre, and for certain applications I prefer the approach.
"The course I am taking they teach to expose for the skin, and not to worry about the background." One thing people forget about portraits, is that the person is the biggest priority, the environment is nice, but I guarantee that bride considers herself the most important element of the composition. Skin color in general can vary substantially in it's reflectivity, necessitating EV adjustments that may or may not equal the environment. So which one do you want exposed properly, the bride's face or the background? IE for a fair skinned person you might have to add +1-1.5 EV to your meter reading to get a properly exposed face with creamy skin, half that for a medium skin tone, and 0 or maybe even - on extremely dark skin. Having a face to the bright side helps to cure a lot of blemishes and tonal variations. That's not to say you can't have an acceptable exposure across the image, by taking the appropriate steps to narrow the DR of the scene, you can show as much or little as your vision demands.
