Condenses the ports to one standard. Instead of an audio and a USB-C, you just have a USB-C. So now you can fit more/different stuff in the internals or streamline the device to make it slightly smaller or thinner. Far enough down the line when most everyone is on board, can remove support for it from the kernel, minimizing the code footprint, attack surface, and code maintenance.
Sure, it sucks now as we’re in the midst of it and people are resistant to change, but fast forward to when it’s universally adopted and accepted, it’ll be better.