IMO the principal consideration here is that these are offline/local databases for browsers and (probably?) Electron, so they are not intended to be scalable at

IMO the principal consideration here is that these are offline/local databases for browsers and (probably?) Electron, so they are not intended to be scalable at all. If you have a progressive web app (PWA) and you need a queryable database for some reason, then you would use these. Otherwise, stick your queries behind API endpoints.