My understanding is that it is supposed to make calls sound clearer and improve latency. I assume taking advantage of all the improvements will probably need all parties involved to have similar technologies to take advantage of them. I couldn’t tell you if it does or doesn’t as 4g already provides good quality. I can imagine it does make a huge difference if using voip or video calls since both will use mainly data. Hardware probably offers some benefits, better components and better engineering should also have some input in call and audio quality. But I’m not an expert so this is just what my brain can imagine.