At the moment, the query service can give results as XML, JSON, TSV, CSV, and RDF if a service sends the correct accept: HTTP header (manual)
However, only XML and JSON are supported as URL parameters (like so).
Not all possible use cases are able to set headers, so it would be good if the service could also offer TSV, CSV and RDF as a URL parameter ("...&format=tsv").
This ticket originated in a conversation on the Telegram chat. One reason to want this feature is to use with https://kepler.gl/demo and the "Load Map Using URL" option.
This would allow for quick and easy mapping of points, paths, etc held on Wikidata.
This process has already proved useful on FactGrid to visualize correspondences on maps, for instance through this query generating origins and destinations of letters about the Illuminati.
It is also proving useful with Uber drivers turned Wikibase users who want to analyze their trip data (setup slightly more complex).