I've seen multiple people claim it works for Windows ISOs and multiple people claim it doesn't work - mostly right here on this site!
I love Etcher. It works great... (most of the time)... with Linux ISO files.
I think I'm one of those who say it won't work with Windows 10, and I'm afraid I have to stick with that story. I just downloaded the latest appimage (1.5.115-x64) from etcher.io website and it still fails me. The GitHub site instructions for adding a repository for Debian/Ubuntu also fails with errors on my Ubuntu-based Zorin, and I'm not interested in trying to fix this. I also have no interest in building it from source, but the source is slightly newer (1.5.121) than the appimage on etcher.io. Burning a Windows USB is just not worth all this trouble.
I have the latest ISO downloaded from Microsoft, Win10_21H1_English_x64.iso, and Windows Media Creation Tool successfully burned this to a USB. I've used that USB for 2 successful installs on laptops recently. So there is no defect in the ISO. If Etcher needs to be run inside Windows in order to burn a Windows ISO, then you might as well use Media Creation Tool instead. If you can get Etcher in Linux to actually work to burn a working Windows 10 ISO, then please enlighten me. Again, though, Etcher should be a "simple solution" and not require building from source.
Wanna try for yourself? You can download Windows 10 from Microsoft here
. It's about 5.4 GB. I suspect that the Windows ISO is not a standard ISO, and that is causing the problem. I have not found any Linux tools that will work correctly, though there are several who claim to work. I am tired of trying... Windows is not worth all this trouble. (Be careful, or I'll say that again!
Etcher fails at the first stage... picking the ISO file. Here is what it shows: