@ar because it’s not always voluntary.
Some teams set "targets" to achieve higher participation rates and scores. When participation rates or manager scores are low, there tends to be extensive discussion and speculation about who might not have submitted their results. Occasionally, employees suspected of this are penalized during feedback and salary reviews. This issue is prevalent in the Signavio teams in India and the Czech Republic. Managers are eager to secure good scores to earn trips to Berlin for offsite meetings. Consequently, team members find themselves competing against one another to get better performance management feedback as it depends less on their goals and more on how good the feedback the team gave to their manager. Managers with lower scores are moved to smaller teams (of less than 7 reports) so their scores are not shared or part of the overall and this keeps bad managers safe. At other times, managers with lower scores move to another team or a position with zero reports for a year before moving into a management role again but with another team.
In some areas like Signavio, one cannot simply neglect this survey because your performance management feedback and salary cycle depends on it.