The desk doesn't have to be empty. You book a 25-minute slot: if someone else books the same one, they're connected on video while working on their own things.
People who work from home lose the background noise of an office and the colleagues around them. A coworking session puts another person in the same video call, without needing to exchange a word.
You book a slot, you find yourself on video with another person working on their own things, and for that time the screen isn't the only thing in the room anymore.
No, many sessions go by in silence: you each say in one sentence what you'll do, then each of you works on your own.
It can happen, if you book the same slots. With the star you can mark a person as a favourite: only you see it, and it doesn't change the matching.
No, it's a free personal account, independent of any employer.