I think it would be a good idea to have a guest account button. This would allow a stranger to use the phone app, but without being able to see your contacts or see your recent calls and without access to apps like payment etc. It would be super nice if they could enter their contact info and it send to the main account. This will keep your things private and safe but allow someone to make a local call or add their contact info. This prevents what recently happened on the news with a stranger sending himself money.
