What is the difference between this receiver and the Vont FM Transmitter?

The Vont Receiver can be used to make your non-Bluetooth devices with 3.5mm INPUT aux jack (such as old stereos) be Bluetooth-capable so you can connect it to your phone or tablet and play music. While the Vont FM Transmitter (https://www.vont.com/product/bluetooth-fm-transmitter-for-car/) is more suitable for making cars into smart cars wherein you can connect stream music and take calls using your car speakers.