Arguing simplification and then using DynamoDB, that is, opaque software handled by somebody else, does not make any sense or useful argument IMHO. It's like saying, we don't want to handle all this stuff, let somebody else handle it so that we can just be users. This is fine if is good for your company, but kinda negates the initial premise: you have a simplification problem if you own your infra, otherwise what's the point? Somebody else is handling all that for a premium price, I bet you have less software to handle.
