OK, so there are lots of bad selfies. We can all agree to roll our eyes at the 15 year old girl who takes 20 a day.
But for the rest of us? There's something special about a selfie, especially a group selfie. When you go on vacation or to some event you can show off a photo, and everyone who is involved in the photo is also in the photo. Think about how unique that is. Normally there is one person who has to be apart, to be separate from everyone else, for a photo to get taken. But a selfie removes that limitation, and lets everyone be part of the moment that will be preserved and remembered forever.