If you need excellent graphics performance (e.g. for games or AR). For better access to cameras and microphone and maybe other hardware such as tilt sensor, fin

If you need excellent graphics performance (e.g. for games or AR). For better access to cameras and microphone and maybe other hardware such as tilt sensor, fingerprint ID, etc. For two-way integration with user's calendar, contacts, etc. Integration with cloud storage services (Dropbox, iCloud, google drive). People are more likely to enable notifications, location access, and the like on an app than a website; and an app doesn't need to be open for notifications to appear. You also get background update services for an app. Drag and drop tends to work better in apps than mobile web (where the gesture often becomes confused with scrolling). And on iOS at least, Apple's ecosystem provides some utilities that let you theoretically get away with not having a server (for purchases, game scores, and the like).