Yeah, you are right. It is perfectly possible to wrap awscli by shell script and do exactly the same thing with what this tool does. However, generally speaking, it will be more and more difficult to test and maintain as a tool becomes large, especially if it's written in shell script. Python has awesome testing library (I love py.test), and the most importantly, has really cool AWS mock library moto (https://github.com/spulec/moto). These are pretty much why I picked Python, rather than bash alias or shell script for this tool.