Group stories are great fun and a feature I seriously miss on Whatsapp. They work well from meme chats to family groups.
There being a killer feature that Whatsapp users are missing out on won't convince everyone but it sure makes me feel less like a nerd when encouraging the switch to Signal.
I find it quite funny that such an obvious feature likely hasn't been added to Whatsapp yet because Meta thinks Instagram is for stories. That's pure speculation on my part though