There is no reason to delete recordings of your commands to Alexa. But, if you want to do so, it may affect how Alexa responds to you in the future. In Alexa app, READ, in {Help and Feedback/User Guide/Alexa app/View Your Dialog History} all about it.
There is no army of people assigned to listen to to the jillions of comments people make to Alexa. Jeeze, be realistic!