https://docs.gravityforms.com/conditional-logic-limitations/ states “When Gravity Forms hides a field via conditional logic, it resets the field’s initial value. Conditional logic dependent on this field will be evaluated with that reset value rather than an empty value which is unexpected.”
I may be mistaken, but it seems to me that the performance of larger forms could be significantly improved if calculated fields hidden by conditional logic were reset to “0” rather than being evaluated at client side using Javascript (https://docs.gravityforms.com/enable-conditional-logic/#performance).