Bookmarked https://wptavern.com/gutenberg-8-1-includes-block-copying-testimonials-pattern-and-patterns-ui-update.
Honestly, it’s things like this Testimonials pattern that worry me a bit. Say you’re displaying testimonials sort of all over your site. (Let’s make it multilingual, too.) You’re now asked to update a quote. In twelve or so locations. (If you’d used a [non-public] custom post type, like [some version of] Jetpack’s testimonials, you’d do this only once [per language].) Luckily, you can now copy blocks around, too, but still.
