Question about API Gateway VPC link and Network Load Balancer

Hi. i associated API GW VPC link and had a latency issue. and i figured it through activate cross-zone load balancing, thanks to the link: https://repost.aws/questions/QU4zhD4Tb4Qg6z9U1YXeMAxg/api-gateway-to-nlb-via-vpc-link-latency-issues

i understand latency can be made, but i wonder why it can be solved through cross-zone load balancing.

can anybody explain some details?

thanks.