Comparing Bound Witness Trees and Rollups

Rollup

A Rollup can be viewed simply as a linked list of data. The final hash allows you to walk backwards through the data to find the specific item you're looking for.

Bound Witness Tree

A Bound Witness Tree is a type of Rollup that contains multiple, unrelated data points. Most often, a Bound Witness Tree is comprised of many Bound Witnesses.

For an example of a more complex Bound Witness Tree with a real-world example, see here.