That's bullshit, CGNAT is likely to cause all sorts of issues that the average users aren't going to realize being caused by their "I"SP (A frequent one : being unable to host video game sessions). They aren't getting real Internet, and are being treated as second tier citizens.

Yeah, my ISP uses it. It does come with some of the downsides the previous poster mentioned: the inability to make myself reachable from $the_world can be annoying, and I get a captcha on Google every time because of "unusual traffic" (I mostly use DDG, but sometimes fall back to it). Also, ACM blocked me at some point because "my IP is infiltrated by SciHub" (their words).

In the end, it's an imperfect solution for a real problem that mostly works well enough.