What is advantage of Code Block Group based method in 5G?

What is advantage of Code Block Group based method in 5G?
As per my understanding it’s use to retransmit particular Code Block Group in case of harq nack.
Instead of whole transport block.
Any other use for CBG?

In case of NR low latency UE request.
NR will pre-empt already on going PDSCH transmission and transmit urgent PDSCH instead.
Here we might get the advantage of CBG which retransmit punctured CBs.
Instead whole TB for the pre empted UE resources.
Same thing no any other advantage I think.