The overhead is around ~60mb with default compression settings - less if you use specialist compression tools like RAR. So if you're worried about the download size, that's a more realistic overhead. If you're worried about the size on disk, why? Modern desktop systems have hundreds of gigabytes of storage.
In my view this doesn't matter. If you're making a small, casual game, why not just put it in the browser? If you're making a larger game, 60mb isn't much, especially when modern PC games are tens of gigabytes big.
I started doing this stuff in 8-bit times, and Construct's rather large overhead for small scale desktop games never sat right with me. After playing around in Godot I do see the point of native exporters in this regard.
Mind, I see the advantages of Construct's approach. But I really think file size, the browser wrapper, and the need to rely on third-party tools to convert the project to work on desktop and mobile platforms are the main downsides when working on smaller games in Construct. I agree it doesn't matter that much when developing medium and larger sized games with a relative large amount of media assets.
I do not agree with your point about small games. I do not want to rely on a browser platform to release a game, and the additional file size overhead for mobile devices is a bit painful to swallow compared to other engines and dev environments that I have been checking out lately. I think it is just one natural caveat of Construct's export workflow - offset by other advantages, of course.
Having said that, it's kinda nice to see a similar small project in Godot be compiled to ~17mb<->24mb, and after compressing the resulting file is ~3.8mb up to ~6mb (platform dependent) versus the compressed ~36mb of the Construct version that blows up to a whopping ~120 up to 180mb depending on the platform.
I admit I might be making a mountain out of a molehill. More importantly, I sincerely hope for Construct 3 to have a proper timeline. That's really the main reason why I have been checking out the competition these past few months. Crossing fingers