We regularly use the Shopping list integration at home, but on my usual supermarket they have black zones with no cell connection, so many times I cannot check my list and I always forget to buy some important things… yeah first world problems, I know… However:
Wouldn’t be nice to have a local database available to the integrations that want to use it? Perhaps HA Companion should have some kind of offline access or so. The main problem will be the data synchronisation and deal with data merges.