GoPro HERO6 Black vs. Sony A7R2

The GoPro HERO6 Black is an affordable 4K camera solution but how does it compare to the Sony A7R2? This may seem like an extreme camera comparison but I thought, "why not?" Available on - GoPro HERO6 Black Available on - Samsung 64GB 100MB/s (U3) MicroSDXC EVO Select Memory Card with Adapter (MB-ME64GA/AM)