Make the comparison like-for-like.
The reference records list Ready-Ready and Voice of the Voyager at 570 base ATK and 24% CRIT Rate at level 80. That is a comparison of their listed stats, not a damage result.
Then read the condition.
Ready-Ready’s effect involves a skill-and-Ultimate sequence. Voice of the Voyager has Ultimate-related conditions. Equal base stats do not answer whether a particular character can reliably meet either condition.
An empty cell is not zero.
A dash means the value is unavailable, rather than zero. Compare the effects and the attributes your character needs.