I went through the svelte examples and I was exited until I reached the If block example:

    {#if user.loggedIn}
      <button on:click={toggle}>
        Log out
      </button>
    {/if}

To me such template language is a huge step back from JSX. JSX is JavaScript, thus you get the full power of the language (JS/TS) with the full support from your editor (type checking, auto-completion, etc.).