Bitcoin is encrypted with the use of hashing and a lot of algorithms to make sure all of the information and address of the transaction is secured. Most of the time we are using websites or application to make sure the operation will be secured and no intereaction and to make it safe, If Bluetooth transaction using bitcoin will be created it is more convenient to send to the people near you. Still, it is hard to communicate with the other party because of the limited range of Bluetooth but if they improve this signal is better. This kind of actions very prone to hackers because they can use the internet and jamming the connection to get or receive the money and identify the transaction.