In both cases we don't need the SIM to have a “real number“. The Monogoto approach is more secure and cheaper. When the device needs to receive an SMS, send an MT SMS with Monogoto API’s. When the device needs to send an SMS, usually it should arrive to the customer backend rather than a “real number“. Monogoto can make sure that the SMS will be sent to the customer backend without any extra SMS termination costs and with enhanced security.