The syntax features I mention only make any sense period within IDEA. But it's just a syntax feature. The value-add is very low! But it's pervasive in Kotlin. That creates the lock-in. In fact, pumping IDEA's seeming value is those features' biggest impact on the average Kotlin developer.

The majority of the valuable code I've written in my life has been Haskell. I do just use emacs, but I heavily use ghci (free and flexible) to aid my understanding.

But most of that Haskell was conceived while I was doing the dishes. So far, my Kotlin has been too tbh.

So IDEA isn't solving the actual critical path of software problem solving. Kotlin and IDEA are sugar for the masses. Nothing more. And I'm pretty sure they know what they're doing when they aren't drunk on their kool-aid.

I think whether you care strongly about syntax is just personal preference. For example, I prefer Elixir to Erlang, TypeScript to JavaScript, and Kotlin to Java even though they could be/are implemented by transforming source code to source code.

On receiver scopes specifically, they make simple DSLs very easy to implement. Arguably needing a DSl is a symptom of design flaws, but Android has a lot of those so receiver scopes makes Android programming a lot nicer.

Edit: I would call this more than syntactic sugar:

    interface MyScope {
        fun frob()
    }

    fun foobar(content: MyScope.() -> Unit) {
        let scope = MyScopeImpl()
        scope.apply(content)
        scope.getResultInternal()
    }

    fun user() {
        foobar {
            frob()
        }
    }