I'm a proponent of "offline first". So my recommendation for any apps - like a wiki - should save to localStorage first, then behind-the-scenes sync up to one's own personal server (alternatively a host provider that a customer can pay to manage on behalf of them). Then if one should ever install a new/another instance of the wiki on another device, the app should download all the latest from the personal server. Anyone who builds such a thing would instantly become a hero! ;-)