What deergomoo says, and also performance - Svelte isn't really a framework, it prefers to call itself a compiler. Each component compiles into something that has no virtual-DOM overhead - what the compiler does is that it tracks which fragment depends on which value, and then at runtime when a value is updated, only the needed fragments are updated.

What I also like about it is what a .Svelte file looks like. Since it's a compiler from the very beginning, it didn't need to start as .js and only than add .jsx for a little less verbosity. Svelte file is basically a HTML file with <style> and <script> tags. Variables from javascript can be referenced in HTML simply with {var}, and there are constructs for if/else, loops and few other special things. Easier to see than describe, go to https://svelte.dev/tutorial/