$ has a looot of gotchas, under some conditions, the reactivity climps up the dependency tree. E.g. https://github.com/sveltejs/svelte/issues/4933

I used to use "$" like useEffect, but now I don't know how to use it anymore

And Svelte still bites my intuitions when dealing with complex objects, most of the times I've manage solve it by separating the code into multiple components, but it's not clear why that happens