1. You shouldn't be on a phone call when paying. It's rude to the clerk and everybody working there.
2. It's also rude to those around you, when in line. We don't want to hear your conversation.
3. You slow things down when on the phone too. People don't realize they are not moving as fast cause they are paying attention to the phone call, not as much as what's going on around them (just like on the highway, usually the idiot in the left lane going only 40 mph is on the phone). Stop the phone call, read the menu and get ready to order and pay.
Do us all a favor , don't use your phone in line, while actually paying or in a restaurant at all. Do use it for Apple pay. If you need to talk on the phone that badly, step outside or stay in your parked car.
Thank you.