Let me put it another way, when was the last time you heard a user ask for an iOS app to be on the Mac? Is this what Mac users want or is it something that Apple wants?
Users, absolutely. Some apps have already done this (Deliveries and Paprika Recipe Manager come to mind). But it's a ton of duplicated effort right now to do that. Paprika's Mac version costs $30 to compensate. There's much less competition here; iOS has a bunch of recipe managers but as far as I know this is the only one with a companion Mac version.
Maybe Facebook will make a Mac client for Messenger (messenger.com works, but some people might prefer a desktop version). Maybe Netflix will have a Mac client (they already have one in the Windows store). We could get Google Maps as an alternative to Apple's native Maps app. Slack could throw away their Electron battery-guzzler and replace the Mac version with one based on the native iOS codebase.
Not every app wants or needs a Mac port, but there are plenty of cases where it could be useful.
I'm right here, as both a user and a developer, and would really like more native apps on the Mac. A unified platform to make it easier for developers to build apps across both platforms seems like an incredibly obvious win.
I love apps that allow me to work on an iPad while I'm on the tube, then pick right up where I left off on the desktop. It’s the best of both worlds.
A good example is Bear Writer[0], a Markdown-based writing and notes app. The Mac app, while fully featured, is based on Electron. Without knowing anything about this new system I’d think these changes would allow the developers to create a native Mac app at least as easily as an Electron web app.
>when was the last time you heard a user ask for an iOS app to be on the Mac
This is something pretty much everyone I know wants that has had both a Mac and iPhone.
There are great iPhone apps and they usually don't have a Mac version. You're stuck whipping out your phone to use some app even though you're already using your laptop.
