From what I can tell from the announcement the change will apply to a NAT gateway, so the cost of that will rise from 0.045 to 0.05, the same as having 10 IP addresses.
If they are really seeing high costs associated with IPs then I would like to see them reduce the price of the NAT gateway to the same as having 3 or 4 IP addresses or less, ideally free then they would probably see a lot bigger uptake.
At very least some free tier for NAT64 gateways, or shared DNS64/NAT64 alike https://nat64.net/public-providers for Amazon users would be nice. I'm fine with ipv6-only connectivity for a lot of hosts, but once in a while they need to download some software / updates from github.com which is still ipv4-only. Paying fixed extra cost for every subnet just for 100MB/mo download per host is meh.
