The list of things that require an app rather than a web page was pretty long circa 2010, but it's quite a bit shorter now: it's mostly hardware access (Bluetooth/NFC), background activities (like background app refresh), persisting location permission, reliable offline storage, and system/OS integration (widgets/live activities, Siri shortcuts).

If done for the right reasons, a native app could theoretically be a bit more power- and bandwidth-efficient for a given level of polish.

But usually what you're getting is some cross-platform mystery meat UI, a boatload of tracking, and no real system/OS integration (because it isn't trivial to do from whatever cross-platform environment they chose).