For example, you use some MVC framework for your web application and for most of the time you are thinking in very object oriented way, and that is why you opted to use an ORM framework in the first place.
However, when it comes to reporting. You decided to use reporting framework like BIRT, for example. BIRT does not know about your object relational mapping, it knows about your tables and raw SQL queries. It suddenly takes away all the abstraction that you've put in place. Nothing wrong with that but it feels rather disconnected (and 2005).
So the question is, why would you use any reporting framework then when you can simply just use aany (HTML5) templating framework out there to render your report. Assuming you don't need the multi-format exporting capabilities of a reporting framework.
Remarks: performance is not an issue ... at all