Having multiple accounts reduces the potential blast radius tremendously. Anyone who hasn't accidentally deleted "stuff" in the wrong account is someone who ha

Having multiple accounts reduces the potential blast radius tremendously. Anyone who hasn't accidentally deleted "stuff" in the wrong account is someone who hasn't been doing production work for long. One big downside is that it makes sharing resources between accounts more difficult...which I suppose might also be an upside, since that dependency needs to be explicit in the various permissions. It also makes tooling more awkward. But, it also allows you to completely automate deployment of consistent environments, providing a IT/CI/Testing nirvana for not that much work.