I heavily vouch for them - the tech is so effective we cover them with a shadecloth in high Summer because the water gets too hot (Off-Grid property in Central West NSW, Australia).
Ours have lasted over 10 yrs without maintenance.
One downside is that they're not ubiquitous so some plumbers may not want to work with them.
They're so good I'm surprised I don't see them everywhere.
They talk about reducing skin friction drag but due to the translation I'm not sure if that's what this article is referring to as well.