it is useful if you want to re-use your existing coaxial infra. I was using powerline for many years (only 200Mbps speed) and was considering whether to go with Coaxial to Ethernet or Wifi6 mesh.
I ended up with Wifi6 (wireless backhaul) which gave me 4.8Gbps speed at close range and weaker 1.6Gbps as I extend the distance between the 2 nodes.