Multivalue answer dns is used widely at Amazon (internally and as an aws offering), but it seems like other providers aren't offering this service.
* https://aws.amazon.com/premiumsupport/knowledge-center/multivalue-versus-simple-policies/
* https://aws.amazon.com/about-aws/whats-new/2017/06/amazon-route-53-announces-support-for-multivalue-answers-in-response-to-dns-queries/
Does anyone know about why this practice is not widespread outside of Amazon? Besides that, any technical references or analysis about multivalue answer DNS would be helpful.