I think claims like "this filter/regenerator TOTALLY isolates from electric line" are only marketing.
If you had enough electronics background to analyze how some things work, you would most likely have a different opinion. A regenerator (if built right) can basically do a lot (actually all at times) of what is claimed.
A conditioner has it's limitations by design. You need to analyze the whole scenario.
Even though you live in Italy, have you ever measured the input, and output of a regenerator, to say you know this to be true?
If the power grid over there is similar to the US, you probably get your power through a variety of materials like we do, including steel, and all kinds of various alloys. Power cords can't change the bad power, to good power, coming from a utility. A regenerator can.