• when building UIs and data visualisations each interaction moves the responsibility away from the designer, and towards the viewer
• in an ideal world, no interaction should be necessary to understand the visualisation - the viewer should see, and then understand
• on the other hand, interactions can be interesting when playing with Simulations, trying to understand the parameter spaces, and get a feel for how things work
• also, interactive art vs non-interactive one - is there something here? - do people engage more with interactive art? - or is it just "novelty" of it?

Interacting with an interface always involves some work on the part of the user. The goal of designers (or at least one of the more important ones) is to minimize that work, while at the same time enabling users to achieve their goals. If designers and developers don't pay careful attention to the human actions required to operate their technology, the result can be a taxing experience for the users.

— About Face