The main draw is that Svelte apps have no dependencies at runtime, instead it compiles a pure vanilla js bundle that relies on existing web APIs to do updates. This is attractive to a lot of people, me included, but imo Svelte isn’t quite production ready yet (at least for complex apps). It’s great for small projects though and I highly recommend checking it out

From what I know it's a compiler, so it check all the things at compile time and not waste time at run time.

That's partially true. The other benefit is that there's no vDOM, the way things change is reactive (kinda like in react), but there's no such thing as a no-op change. if you set something to what it was, it would trigger a partial rerender so you have to check before setting. With react you get those checks for free (provided you comply to certain restrictions).