This would definitely be hugely helpful. It is the only reason we have ever considered swicthing back to Calendly.
It is pivotal to let the guest booking the meeting add additional guests.
It would also be great to default the addition of internal folks. For example, for every meeting booked through this link, I want to make sure my coworker is also included. You can currently have the meeting link ensure two calendars are available, but you cannot automatically have the other person invited as far as I know.