I don't know whether powerline adaptors have been improved, but they gained a reputation in their early days for spraying the vicinity with wideband radio interference*; the amateur radio people did not love them for it, as they're always seeking faint signals from distant lands. There's many Web articles saying "it's not a problem, honest" .... on the sites of adaptor manufacturers.

I've inherited an amateur-radio receiver. One of these days, I'll drag it out, and find out for myself whether the powerline-adaptor link for our upstairs phone (mea culpa, but we had little choice) is as noisy as alleged. I'll report back.

* House wiring rarely follows best radio-frequency practice.