A watch only wallet means you can see your #bitcoin account details but cannot spend from it because it does not have your seed words (private key).

You can generate new receive addresses to send bitcoin to this wallet through your watch only wallet without your seed words.

You can use your watch only wallet to set up a payment but need to use a your seed words to sign/be able to spend. Easily accomplished with a hardware wallet that has no access to the internet.

The hardware wallet communicates with your watch only wallet via camera and QR codes to send the signed payment.