I wouldn’t be surprised if a stripped-to-the-bone installation of WinXP in a VM, running only Paint, is lighter on system resources than Electron running this.
A very basic XP install with a GUI can fit in 20-30 MB[1][2][3], using minlogon, but even with a "standard" Winlogon it should be below 50 MB, so it surely would take less disk space than the hypothetical 100 MB electron based version.
It can be packed very easily actually! It is a single HTML file, so you can easily embed it into an electron app or a webview if you wanted. Only problem is it would bring the total size to ~100 MB instead of ~1 MB, and would be tough to make it a single .exe file.