One of the unqualified good aspects of the web is that its text based format made it simple for anyone to view source to learn how the structure of webpages worked, so they could apply that knowledge themselves to their own websites. It also made it possible to build websites using only a text editor. Text-based formats are also easier to edit or script in a browser.
Binary formats may be easier to parse but ethically they go against everything the web (or a web alternative) should be about.
And even though HN is heavily anti-JS, especially in threads like these, I'll be the contrarian and say that being able to run code on the web (or an alternative web) is absolutely critical to maintaining software freedom because it allows anyone to easily create, distribute, edit and run software. The problem with the web itself isn't that you can run code in the browser, it's that (until recently) the only code you could run was Javascript, and HTML and CSS are terrible substitutes for native UI.
Now you can bootstrap and run just about any software in the browser. Software and game preservation become more vital when you can actually run old software without needing old hardware.
A web alternative needs to be designed to maximize freedom for the end user, not convenience for the programmer.