VoLTE mobiles support voice and video calls on data with native dialer. With 4G LTE, you cannot do voice or video call using your data. With 4G/LTE you have to use other apps like Wattsapp to do so. 4G LTE allows faster data usage though. 4G and LTE are 2 separate things - 4G was developed to support online browsing, downloads. LTE enables high-speed data on mobiles. But with VoLTE, you can directly use this data to do normal calling and that too with more clarity. The only drawback is that the person whom you're calling too should have VoLTE phone. But again, that's nothing, because the connection takes couple of seconds at max and on top of that voice clarity is good too. If you're doing video calling the picture quality is excellent. Moreover, you can switch between voice and video calls in the middle of the call. With a VoLTE phone, if you want to switch back to 3G or 2G services, you can do it.
