An update replaces the program but keeps your data. Most post-update failures happen at that seam: the new version expects settings or files in a different shape and stumbles on what the old version left behind.
Operating system requirements are the second cause. Apps steadily raise the minimum version they support, and on an older device the app may install but fail at the point it needs something the system cannot provide.
Permissions are sometimes silently reset. An app that loses access to the camera, microphone or storage will often fail in a way that looks like a crash rather than reporting the missing permission clearly.
Because the data usually survives a reinstall, removing and reinstalling the app is safer than it feels — but only when the account and its data live on a server rather than solely on the device.