I don't believe it will give you better audio, certainly not as a blanket statement. I have my smart tvs connected to sound via HDMI ARC (or optical in one case) and the audio system passes the same feed as if I went through a streaming box--even if the audio originated from a streaming box. And this works perfectly with the TVs' own apps, OTA, game consoles, or streaming boxes. The "receiver" is back to handling what it should handle: audio (and not video, combining/switching multiple inputs, etc.). Less wires, less aggravation, and excellent audio.
Mike
A receiver is meant to handle all of that. That’s why it’s a receiver and not just an amplifier. Most TV’s also have inputs with a varying hodge-podge of capabilities. Even on my 2017 Sony, only two inputs can handle enhanced formats like HDR. With a receiver I can have up to 8 devices connected, all capable of getting enhanced formats to the TV. If I have one port on the TV taken up by the receiver for ARC, another by the ATV 4K, where does that leave me with another device like a PS4 or XB1? Either using a stand-alone switching box, which is rather silly consider that it’s part of a receivers job in the first place, or manually plugging in devices anytime I want to use a device with enhanced formats. When used properly and to their full capabilities, receivers are an integral part of any home theater.