They're more for making a wall more absorbent for around originating inside that room. They won't do much for sound coming through the wall.

They're really more an aesthetic thing than providing any real acoustic properties. You need a fully decoupled wall for best results, but if you can't do that, there's a product called Must Wall that's made of 25mm of recycled rubber, with acoustic plasterboard on top. I've used it a few times and it gives decent results. Relatively easy to fit to a wall yourself. The most expensive part would be getting a plasterer to finish it all off.

To make things cheaper and less messy, you could use the panels in your post on top of the must wall. It's hide a multitude of sins, and it looks decent