Can I use the video feature with someone who is not registered on the platform

Yes, you can invite anyone to a video session, no matter if they are registered on the platform. 

In your profile dashboard go to Video Center, copy and share your waiting room link with your client. You can also invite a client to a call by sending them an SMS to their mobile phone or via email. To do so click on the Start Video Call button below your profile picture or in your Video Center. Select the invite option and follow the invite instructions. A message will be sent to a client who can join a video session on their desktop, mobile or tablet.