I'm betting this is the real end-goal of WSL. MacBooks were once expensive, but high-quality, grab-and-go unixy development machines. Now, they're mostly just expensive.
When WSL matures, any commodity laptop will be a cheap, decent quality, grab-and-go unixy dev machine. It'll probably be easier and more reliable than installing Ubuntu directly! At that point, web and server devs will migrate en mass from Mac to Windows.
Then they will discover Clang for Windows and that dev tools for Windows in general are actually pretty nice. And, since they are already running their server code on WSL, it becomes much easier and more interesting to get it running in Windows directly. Bang! Huge uptick in open-source server development on Windows.
When WSL matures, any commodity laptop will be a cheap, decent quality, grab-and-go unixy dev machine. It'll probably be easier and more reliable than installing Ubuntu directly! At that point, web and server devs will migrate en mass from Mac to Windows.
Then they will discover Clang for Windows and that dev tools for Windows in general are actually pretty nice. And, since they are already running their server code on WSL, it becomes much easier and more interesting to get it running in Windows directly. Bang! Huge uptick in open-source server development on Windows.