> - Native apps can accurately determine exactly what operating system and browser you're using, while web apps either have to rely on a User-agent (which is trivially spoofed), or perform fingerprinting in order to come up with a guess
A native app may know which browsers I have installed, but how would it know which of the umpteen ones I have I actually regularly use (if I don't do so while running the app)? The Web app, OTOH, is running in that browser, so yeah, of course it has a better chance of knowing that.
True, but to be fair, most users (Windows users, at least) don't have more than 2 browsers installed (Edge and either Firefox or Chrome, and it's likely a safe bet that if FF or Chrome are installed, that's their preferred browser). *nix users likely only have 1.
Your "umpteen" browsers is very much an edge case.
A native app running under your account can do anything you can do, so it can determine which browser you use by any number of methods, for example by checking the timestamps on the files in your various browser profiles (and of course read your browser history etc.).
A native app may know which browsers I have installed, but how would it know which of the umpteen ones I have I actually regularly use (if I don't do so while running the app)? The Web app, OTOH, is running in that browser, so yeah, of course it has a better chance of knowing that.