[derefr]

> you should write a custom UI for each platform you're bringing your logic to

The question isn't of "bringing" your logic to a platform, though. The question is how people who you don't care enough to provide first-party support for, will run your application.

Consider a situation where someone codes native apps for Windows and macOS, but also provides an electron app as source. Who is that app for? Everyone who is using any other platform.

Also consider the "native-ized" apps that exist to wrap web-apps that never created a native app at all. For example, there are numerous Electron wrappers for the Facebook Messenger web-app created by third parties who just wanted to be able to use Facebook Messenger on their PCs as an "app" rather than a webpage.