This is a good fit for any time you want to share some static data with the world - instead of posting a CSV file, you can share your data as a Datasette instance with a browseable web UI and a JSON API instead.
The three use-cases I'm personally most interested in for this are:
Data journalism: newspapers collect data about e.g. police shootings https://vice-police-shootings.now.sh/ or actions under the antiquities act https://fivethirtyeight.datasettes.com/fivethirtyeight-2628d... - I want to make it as easy as possible to publish the data beneath the stories.
Government open data: cities like San Francisco publish huge amounts if interesting data. I used San Francisco's 190,000 line CSV of trees in the city to build https://sf-tree-search.now.sh/
Cultural institutions: museums, libraries and art galleries have the collection and sharing of data as part of their mandates. I want to make it as easy as possible to build things like the London Science Museum's collection API: https://group.sciencemuseum.org.uk/about-us/collection/using...