What is Nessus Essentials? Why use it for application scanning? This video provides a little background before jumping into the demo.
Regarding the list of DAST tools, you might say, "What about Acunetix?" There are many other free and paid DAST tools on the market. I have listed just a few that I have direct experience using. For a list of alternatives, see OWASP's list of vulnerability scanning tools: https://owasp.org/www-community/Vulnerability_Scanning_Tools
