Crystal reports with SAP ECC scenerios

Hi All,

I understand that with sap integration kit we can connect crystal reports with SAP BW objects as well as ECC tables and FMs.

i want to know in which case we use reports out of ECC tables and FMs considering performance would get affected.

Is it possible that without using SAP BW as back end we only implement reports on ECC tables and FM's if yes what is the situation where in we use this option.??

Thanks,

Vishal