I've previously used powerline adapters with no problems, but they're unpopular with radio amateurs for a reason... Try them out in your system, if you don't get any interference/noise then that's fine.
Alas, it isn't always that simple.
Firstly, not encountering problems on initial test doesn't ensure they won't arise later on when you change something else - that may seem totally 'unconnected' (in the general sense of the term) but *is*. e.g Adding or removing some other mains powered item in the house. Or something in your mains wiring and devices developing a nonlinearity it lacked previously.
Secondly, you may be causing interference for a neighbour... and they may do for you, because of the above.
As pointed out already, home mains wiring was *not* designed to convey wideband RF and has all kinds of spurs etc, that make it into an antenna system. For example, conventional wiring to a light hanging from the center of the ceiling tends to act as an unbalanced spur when switched *off*. But less so when switched *on*.
Frankly, these systems should never have been approved in the first place. They only did so because they were considered *without* any house wiring attached! Reason being no-one could properly test for all the likely types of home wiring and device arrays they'd be used with in practice. They got approved for purely commercial reasons, and then public demand for their 'magic' ability to save people having to install something like ethernet wiring.
Fortunately, most well-designed kit these days will have been made by someone who knows what the above means. But in reality it is impossible to cover every possible example.