AWS is planning to charge for all allocated IPv4 usage, but many of their crucial services do not support native IPv6. This includes AWS Cloudformation and AWS systems manager, which require an IPv4 address or a NAT gateway to work. NAT gateways can be expensive, so the author is calling for AWS to provide IPv6 endpoints for all their major services. This post serves to raise awareness before the IPv4 fees begin next year.
https://old.reddit.com/r/aws/comments/17rxig8/aws_wants_to_start_charging_for_all_allocated/