NTA is mainly used to show the breakdown of traffic of a certain interface. For example you have a router and you have enabled netflow on it >> monitored on interface port 1 on NTA application - what you can get from it is the Top Endpoints (more like Top talkers) that utilize your bandwidth given on a specific time. It can also display the conversation reference to top endpoints - to show what or where is that endpoint is talking to. It can also show the top application, protocols, domain that interface is having on a given time.
If you want to monitor like a server performance going to a certain database like volume information, it will be the QOE feature for NPM.
NTA is more on the tool to help network engineers to track network issue.