Rna polymerases carry out transcription at much lower rates than dna polymerases carry out replication. Why is greater efficiency more important in replication than in transcription?

This depends on the speed and duration of enzymatic activities of the two enzymes.

DNA polymerises need to replicate the entire long length of DNA strands, thus enough time commitment and energy is needed for this. Therefore greater efficiency should be available to undertake this.

However, RNA polymerase do not need to transcribed the entire length of the chromosomes, only the essential small regions (exons) of the DNA need to be transcribed. Thus lesser speed and time is committed with low energy. and efficiency.

DNA polymerase is responsible for the catalysis of the replication of a vast region of DNA and the efficiency/speed of the replication is necessary to complete the replication process swiftly.

Explanation:

The difference between replication and transcription, is that in the replication process the DNA is making more copies of itself and in transcription, the DNA is being copied into RNA. DNA replication occurs in preparation for cell division, and transcription occurs in preparation for protein translation