As per the following docs, All environments will consume 1 GB in Dataverse capacity, regardless of whether they have an associated database.
https://docs.microsoft.com/en-us/power-platform/admin/capacity-storage#im-a-power-appspower-automate-customer-and-have-environments-with-and-without-database-will-they-consume-storage-capacity
This behavior is confusing to customers as it consumes 1GB by default regardless of usage. Also, some customers are complaining that 1GB is being consumed without the consent of the user. Therefore, we hope it doesn't consume 1GB by default.