Good reminder at PMThink about including intangible benefits in the business case (here). It is a short but spot-on post.
The trick is to re-visit them periodically to make these benefits tangible. Often what makes benefits intangible that they’re hard to measure — e.g., the data may not be available until the deliverables themselves are created.
A listed intangible benefit should include its proposed measures in the original business case, so that one knows what/how/when to measure one the deliverable starts generating outcomes (and hopefully benefits).