Why didn't you use Exactly Once semantics in Kafka?

Exactly Once semantics in Kafka require enabling transactions and more complex processing logic, which increases system load and reduces performance. In some cases, when speed and throughput are critical, and absolute guarantee of single processing is not necessary, At Least Once or At Most Once semantics are used. Also, Exactly Once is more difficult to configure and debug correctly, especially in distributed systems with many producers and consumers. Therefore, if business logic allows for message reprocessing or compensating actions, it is possible to abandon Exactly Once to simplify architecture and improve performance.