Some customers use a mix of reservations and on-demand usage for BigQuery.
As of right now, the dashboard isn't as useful for companies with reservations. Lots of noise.
In the future case when we support reservations, a customer still may want to differentiate their recommendations between types of queries (on-demand, reservations, programmatic).
Feature Request:
Option to exclude queries executed with reserved slots
Bonus: Option to exclude programmatic queries