To say that you never have to think about those considerations in Svelte is pretty unfair - reactive declarations/statements are functionally equivalent to hooks, and they also carry a somewhat nonintuitive cognitive load until you've begun to "think in reactivity". It's also worth considering that hooks, while unintuitive in function, do use intuitive, non-magical syntax (unlike Svelte's reactive syntax). FWIW I like both, I just think they're both equally unintuitive until you make the mental connection.
I guess we're all different, but I've never had to think much about reactivity in Svelte.
Most of it can be explained in a HN comment:
Component state just does its thing. You change it with = and the component is re-rendered.
Writable stores need to trigger changes with set() and you need to use $ whenever you reference it in a .svelte file so that Svelte handles subscription automatically.
Reactive statements $: are a bit more complex. Every variable inside those is referenced by the compiler so that it knows when you are mutating it. Either with = or if it's a writable store with set().
