Advantage of ARC (AUDIO Return Channel)

ARC or Audio Return Channel uses a single HDMI connection to send audio from one device to the sound system. This is mainly to avoid old optical cable and circuit. On your TV or soundbar, one of the HDMI inputs will be labeled “ARC.” That is one of the best features to connect to the home-theatre — you can save you money and reduce your cable clutter. ARC and audio-over-HDMI it’s not entirely perfect. It was designed specifically to replace S/PDIF digital audio outputs (TOSLINK) and supports audio formats which are supported by S/PDIF – Dolby Digital, DTS and PCM audio. It can obviously handle regular two-channel and 5.1 surround sound. ARC is an audio link direction is used when the TV is the one that generates or receives the video stream. Without this ARC feature, the audio output from the TV must be routed by another cable, typically TOSLink into the sound system. The features first discussed on 1.4 specification:

HDMI 2.1 specification has a new and improved audio technology, called Enhanced Audio Return Channel (eARC). eARC supports full-resolution audio signal such as Dolby Atmos and similar uncompressed sound.

https://thecustomizewindows.com/2018/11/what-hdmi-arc-earc-hdmi-cec/