As someone who wrote his first lines of JS in 2001, working with Svelte feels a lot like the good old days of JS when front-end was simple. To me the main selling point is that the stack trace is actually useful for a change - you especially can find in there the line which caused the re-render and subsequent error. JS frameworks/libraries by and large lost that feature a decade ago.
This was initiated by Angular team, but I have seen it work for vue as well