App processes are sorted in order of most recent use, keeping the most relevant ones at hand, and those that aren’t used for a while just silently go away without much fuss.
In comparison browser tabs aren’t organized unless the user does that themselves, and so with each web app tab management overhead increases. Some browsers have an idle tab auto-close feature, but that closes the wrong tab (usually a page with info pertinent to something I’m working on) quite often. “Installing” PWAs can be an ok-ish workaround, but the problem there is that a lot of sites don’t have the little bit of manifest magic that makes saving to home screen “install” a PWA instead of just opening a browser tab.