I've seen this on whatsapp where you can take appointments via whatsapp without leaving the platform, which offers a great customer experience. I've attached an image of another company using the Whatsapp API to achieve this.

Use Case: I had a customer ask me if they could chat with me and I would like to just send them a message with the times I'm available and they can easily book in without leaving the platform. Also very useful in automations as well to prompt customers to book and get more customers!