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.
[1] http://reboot.pro/topic/3717-xpsp1-with-full-commandline-and...
[2]http://reboot.pro/topic/16765-minixp/
[3]http://mistyprojects.co.uk/documents/MiniXP/