One of the most beautiful and attractive thing about whatsapp web is that if you do not want to use your phone you can still have a chat with your friends on laptop. No need to use a mobile and laptop together.
It scans a QR code which provides a very good security to your personal messages.
You can chat with your friends, call them all on a laptop.
It too notifies you which laptop is using your whatsapp with its details and you can log out from all laptops by just pressing "logout".
So have it and enjoy.
Thank you.