Sometimes, you want to be able to support more than one OS.

You mean like download qt and make an app that compiles on everything and integrates much better than a webpage while also being much faster and smaller?

Don't expect me to download your .exe if you're solving a problem that can be solved using a web app.

Don't expect me to care if my exe solves your problem but you are too stubborn to use it.

If you don't care about what your potential users want, that's fine, but I don't see why you would be partaking in an argument that's mostly about trying to reach more users.