This is really only tangentially related to the article, but

>If AWS responds that there is no current capacity for m7a instances, the instance is updated to a backup type (like m7i) and started again

Any ideas why m7i would be chosen as the backup type rather than the other way around? m7a seems to be more expensive than m7i, so maybe there's some performance advantage or something else I'm missing that makes AMD CPU containing instances preferable to Intel ones?