Homeplugs (ethernet over power) are fine for some things, but they add so much latency to the network.
Wired is so much better.
If you use these powerline plugs, your house is also a huge antenna.
My internet access dropped occasionally until a telcom guy found the culprit. It was a neighbor using a Devolo powerlan adapter.
So yes, don't use these. The only useful frequency in power cables is 50 or 60 Hz.