JExcel is definetly for you if you have Jira Core or Jira Software licence and ...
you are just getting to know Jira
you are heavy users of it but
use Excel and Jira simultaneously
miss some Excel-specific features from Jira like
an Excel-like view of their issues
an Excel-like way of editing issues
copy-paste (also to/from MS Excel/Notepad)
an Excel-like way of filtering and sorting issues (without JQL knowledge)
So, JExcel is basicly for anyone who has to deal with issues in Jira.
If you can't find the feature you are looking for, please feel free to let us know and we'll try to implement it as soon as possible!