Turbonormies, as you say, tend to use gzip not xz. Which is sad because gzip is just as bad for archiving. A few bytes changed and your entire file is lost (in a .tar.gz it means everything is lost).

Frankly, tarballs are an embarrassing relic, and it's not the turbonormies that insist they're still fit for purpose. They don't know any better, they'll do what people like you tell them to do.