This is mostly true, but there is a case where you use your transfer pool.
From their product docs:
Droplets have their own transfer allowance, independent of Spaces. Traffic from Droplets to Spaces does not count against your Spaces transfer allowance (because inbound bandwidth to Spaces is free), but does currently count against your Droplets’ outbound transfer allowance.
From their product docs:
Droplets have their own transfer allowance, independent of Spaces. Traffic from Droplets to Spaces does not count against your Spaces transfer allowance (because inbound bandwidth to Spaces is free), but does currently count against your Droplets’ outbound transfer allowance.
https://docs.digitalocean.com/products/spaces/details/pricin...