Looks neat but I don't know why you'd choose it over one of the big 3 (React/Vue/Angular). Seems to have far less community support and 3rd party libraries available. If you're a business it's probably harder to hire for too as it's less well-known.
Not everything needs to be thought of as a business use case, you don't always need to think about the ability to hire additional developers who know your framework of choice. Also when I'm hiring I care very little about whether people have experience with the framework we use (Angular). Even still, I think svelte can be a good choice if your focus is on enhancing html with javascript rather than focusing on javascr…
"you don't always need to think about the ability to hire additional developers who know your framework of choice"
Unless you are hiring a junior dev who has no experience I think this statement is pretty far fetched. The ramp up time for a new dev on a framework that isn't widely adopted yet will be way higher, plus hiring developers who would even want to work with said framework sounds like a task in itself as well.
If you want to enhance HTML use Vue, if you want to focus on Javascript for everything use React. I like the idea of Svelte coming in to push other frameworks forward, but by no means do I think Svelte will be the future (this may not age well, but at this time my opinion).