Are worth the weight.
We use lightweight gear to move easily and efficiently in the mountains. It is easy to fall into a heuristic trap and believe that “anything extra will make me slow”, losing sight of “easy and efficient”.
After half a season of touring with radios, I am certain that they make us faster and safer. Remember that time you lost your partner in the woods and you each spent twenty minutes looking for each other? What about the time that you lost sight of your partner around a dogleg on an uncertain route; is it safe to follow, or is she coming back up? What about that time you skied first, you had something important to say, and the rest of the party couldn’t hear you?
Doug Krause calls radios “an effective means of communication” (n.b. the linked podcast discusses what radios can’t do). He’s right.
What can you do with a radio that you can’t do without? You can ski longer pitches at once. You can stop in safer locations, out of earshot and sight. You can tell your partners when you just ate it in deep snow and it will take you five minutes to find your gear. You can communicate with a partner who got too far ahead of you on the ascent. At a ski area, anywhere in the world (check local laws), you can stay connected to your party.
BCA’s BC-Link radio is the current Cadillac of backcountry radios, but simple FRS/GMRS walkie-talkies will get you started for less than the cost of a lift ticket. Try ’em with your partner this winter, and see if it changes how you ski.