It seems you've figured out the macOS behaviour already.
The reason it works like this, is that you can now take the
distro folder and put it onto a Windows or Linux machine simply by copying it over. It will just work!
The slightly longer explanation is that this platform-independent distribution saves time and money better spent on developing the application.
The even more detailed explanation is that;
- The dedicated distro folder makes support easier and more cross-platform as well, with a single location for files (such as license and logs) that is the same for all platforms.
- It allows for fast cross-compilation, deployment and an agile, rolling-release schedule.
- It removes the need to rely on bloated platform-dependent installer code (which would increase download size by a multiple!), or create separate platform-dependent downloads
- It provides independence from Apple and its commercial practices that drive up costs and effort for small-time developers.
The install base for macOS is quite small, so it's a fine balance between supporting the platform and dedicating resources to it. The current way of working ensures that macOS users do get the latest and greatest versions, along with everyone else. I do apologise for the hoops you have to jump through however - in an ideal world, the experience would be better.