I think it's the reverse. If you write pure functional components, React is very understandable. It's easily testable, you know that you'll have the same output if you pass it the same props. Svelte templates just take us back where we've been, with the twist of compiling the templates, which I believe some templating libraries already did.
You can dive down and learn the inner workings, the same as you can dive down and learn how the svelte compiler works, but it's not needed for either one. Understanding the concept is more important.
