Also, HaXe is the only viable technology which enables a high-quality canvas-based applications which mirror native applications (while also permitting compilation to those native applications).
I suppose you're not counting the likes of NW.js and Electron because the native version isn't really native - though from the user's perspective, it can feel as native as a Haxe application, assuming they don't look at the ridiculous distributable size and RAM usage of the NW version.
Even then, this still leaves C/emscripten which can also fulfill those requirements, and with similar output sizes (I've tested both and compared the sizes of the resulting web versions, seems that both have an overhead of 1-2 MB for a small graphical application). It depends on what you're planning to do, but one problem I found with Haxe is that it's lacking a good general-purpose UI library that also works well on the web target. Only lower-level graphics libraries.
Even then, this still leaves C/emscripten which can also fulfill those requirements, and with similar output sizes (I've tested both and compared the sizes of the resulting web versions, seems that both have an overhead of 1-2 MB for a small graphical application). It depends on what you're planning to do, but one problem I found with Haxe is that it's lacking a good general-purpose UI library that also works well on the web target. Only lower-level graphics libraries.