Yes, he is using an iPad + remote Linux machine + network connection. It’s an interesting and useful combination for some use cases. You’re right that “you can’t really seriously work offline [for software dev] on it”, at present due purely to Apple-imposed software constraints, IMHO. Regarding “not suiable for any efficient and high quality content creation”, there are some use cases where the iPad 10.5 Pro is pretty useful:

- with an Apple Pencil, it’s a very useful device for sketching out ideas (much like a piece of paper is, but with some neat advantages, e.g., infinite size, scalability, editing),

- with the keyboard and any text editor, it’s useful for banging out text, e.g. a rough draft of a blog post or paper...