Yann
Relationships between lists & records become powerful when we can actually access data from the linked record. For example, if many tasks are linked to a "Feature", it'd be great to:
  • access the Feature's linked Docs from the task
  • rollup the tasks progression or sprint points, to visualize how completed the Feature is, how many sprint points it represents, etc.
However the rollup fields are limited to a surprisingly few (and only numeric) types of values — which don't seem to work. Attached is an example of an attempt to rollup sprint points for a linked feature.