if you are not on Amazon, you are forced to use something other than Amazon's services. Another would be vendor lock-in. If your code is tied to Amazon, you a

if you are not on Amazon, you are forced to use something other than Amazon's services. Another would be vendor lock-in. If your code is tied to Amazon, you are then also tied to Amazon, without engineering resources to divorce. Another reason is, if you are cross-cloud, and not tied to only Amazon. Also @organsnyder's point in the other comment is also true. But certainly, if you are married to Amazon, there is nothing wrong with staying married, if it's working out for you and using the EC2 parameter store w/ KMS. Vault can also work under Amazon just fine, so you can use vault under Amazon, and avoid some of the above reasons.